Patent Description:
A U-SIG field is used in the IEEE standard <NUM>. 11be (Standard for Information technologyTelecommunications and information exchange between systems Local and metropolitan area network of May <NUM>) to convey information to all receivers about various important parameters such as a standard version (<NUM>. 11be or later version), a bandwidth, a number of extremely high throughput, EHT, signal (EHT-SIG) symbols, etc. The receivers include both access points (AP) and/or stations (STAs). The U-SIG is composed of <NUM> Orthogonal Frequency Division Multiplexing (OFDM) symbols, and each OFDM symbol contains <NUM> information bits.

Since the standard <NUM>. 11be is divided into two releases - Release <NUM> and Release <NUM>, and Release <NUM> is in the progress of study, some bits within the U-SIG field are reserved.

There is an agreement to divide these reserved bits into two types:.

In a trigger-based (TB) PPDU, the sequence of disregard bits is copied from a trigger frame. Said trigger frame is transmitted by APs, and indicates to STAs that they can start transmitting, as well as relevant information for those transmissions (e.g. where to transmit, what modulation to use, etc.).

The sequence of disregard bits may cause problems of performance for TB PPDUs. For example, if all disregard bits are set to <NUM>, it will yield an un-necessarily high PAPR of the entire U-SIG field, which may require the transmitting STAs to increase the power amplifier backoff, which reduces the transmit power. If the STAs do not increase the backoff, the high PAPR may cause distortions to the transmitted signal (due to, for example, clipping of the time-domain signal).

The document "PDT PHY Update to Preamble U-SIG" from Sameer Vermani (QUALCOMM) proposes a draft update to the U-SIG field in the preamble section for the IEEE <NUM> standard family, specifically for EHT (Extremely High Throughput) PPDUs. The document describes that the U-SIG field carries information necessary to interpret EHT PPDUs and that that the U-SIG field is designed to bring forward compatibility to the EHT preamble via the introduction of version independent fields.

It is an objective of the present disclosure to provide a method and apparatus for reducing a PAPR for transmitting TB PPDUs, in particular the PAPR of the U-SIG field, thereby improving the transmitting performance of the PPDU.

The foregoing and other objectives are achieved by the features of the independent claims.

According to a first aspect of the present disclosure, a communication device as claimed in claim <NUM> for transmitting a physical layer protocol data unit, PPDU, to one or more receiving devices is disclosed. The use of any of the sequences in the set of sequences recited in claim <NUM> as the sequence of disregard bits allows achieving an even more reduced Peak to Average Power Ratio (PAPR), thereby allowing the STA to refrain from increasing the power amplifier backoff and transmitting with higher efficiency. Alternatively, it reduces the probability that the STA's transmission, in particular that of the U-SIG field, suffers from distortions caused by the high PAPR (due to, for example, clipping).

According to a second aspect of the present disclosure, an access point as claimed in claim <NUM> for transmitting a physical layer protocol data unit, PPDU, to one or more communication devices is disclosed. The use of any of the sequences as claimed in claim <NUM> as the sequence of disregard bits allows achieving an even more reduced Peak to Average Power Ratio (PAPR), thereby allowing the STA to refrain from increasing the power amplifier backoff and transmitting with higher efficiency. Alternatively, it reduces the probability that the STA's transmission, in particular that of the U-SIG field, suffers from distortions caused by the high PAPR (due to, for example, clipping).

According to a third aspect of the present disclosure, a method as claimed in claim <NUM> for transmitting a physical layer protocol data unit, PPDU, in a communication device is disclosed. The use of any of the sequences as claimed in claim <NUM> as the sequence of disregard bits allows achieving an even more reduced Peak to Average Power Ratio (PAPR), thereby allowing the STA to refrain from increasing the power amplifier backoff and transmitting with higher efficiency. Alternatively, it reduces the probability that the STA's transmission, in particular that of the U-SIG field, suffers from distortions caused by the high PAPR (due to, for example, clipping).

According to a fourth aspect of the present disclosure, a method as claimed in claim <NUM> for transmitting a physical layer protocol data unit, PPDU, in an access point is disclosed. The use of any of the sequences as claimed in claim <NUM> as the sequence of disregard bits allows achieving an even more reduced Peak to Average Power Ratio (PAPR), thereby allowing the STA to refrain from increasing the power amplifier backoff and to transmit with higher efficiency. Alternatively, it reduces the probability that the STA's transmission, in particular that of the U-SIG field, suffers from distortions caused by the high PAPR (due to, for example, clipping).

According to a fifth aspect of the present disclosure, a machine-readable storage medium having stored thereon processor-executable instructions is disclosed. When executed by a processor of a device, said instructions cause the device to implement a method according to any of the methods disclosed.

According to a sixth aspect of the present disclosure, a computer program product comprising a computer-readable storage medium having computer-readable instructions stored thereon is disclosed, the computer-readable instructions being executable by a device comprising processing hardware to execute any of the methods disclosed.

According to a seventh aspect of the present disclosure, a computer storage medium, or computer program product of any one of the methods of reducing PAPR is disclosed.

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 to which embodiments. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments, exemplary methods and/or materials are described below.

Some embodiments are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments may be practiced.

Before explaining at least one embodiment in detail, it is to be understood that embodiments are not necessarily limited in their application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. Implementations described herein are capable of other embodiments or of being practiced or carried out in various ways.

<FIG> shows a system for reducing the PAPR in a field of PPDUs according to some embodiments of the present disclosure. System <NUM> includes an access point (AP) <NUM> and one or more stations (STAs), for example STA <NUM>, STA <NUM>, and STA <NUM> shown in <FIG>. The system <NUM> is also called basic service set (BSS) in the present disclosure. In system <NUM>, the AP and the STAs communicate in both downlink and uplink. The arrows between AP and STAs shown in <FIG> only show downlink, but it should not be understood as a limitation of transmission.

Although the system <NUM> shows only one AP in the system, the system may include more than one AP in the system and the APs in the system may perform coordinated transmission.

The system <NUM> in the present disclosure includes but is not limited to: a wireless fidelity (WIFI) communication system, a narrowband internet of things (NB-IoT) system, a long term evolution (LTE) system, a <NUM>th generation mobile communications system (<NUM>) or beyond, a machine to machine (M2M) communications system, or the like. The LTE system and <NUM> or beyond may integrate a WIFI system.

In the present disclosure, a communication device may be AP <NUM> or STAs, and a STA may be, for example, a mobile phone, an intelligent terminal, a tablet computer (tablet), a notebook computer (laptop), a video game console, a multimedia player, vehicle which supports WIFI, device to device (D2D) equipment, or any smart devices. The AP and/or STA may be stationary or mobile devices.

The WIFI system may support all the Institute of Electrical and Electronic Engineers (IEEE) <NUM> serials including but not limited to: <NUM>. 11a/b/g, <NUM>. 11n, <NUM>. 11ac, <NUM>. 11ax, <NUM>. 11be or beyond.

<FIG> shows a U-SIG design for a TB PPDU in <NUM> be Release <NUM>. The bits contained in the U-SIG's first symbol of TB PPDU convey information about the PHY version (e.g. <NUM>. 11be or a later version of the standard), the BW (e.g. <NUM>, <NUM> etc.), whether it is a DL or UL transmission, the BSS Color which differentiates between possibly different neighboring BSS values, TXOP which may include duration of the TXOP and/or how long the transmitter is taking advantage of the channel resources. The bits contained in the U-SIG's second symbol, for a TB PPDU, convey information about a PPDU type (e.g. MU, TB), spatial reuse (e.g. spatial reuse <NUM> and spatial reuse <NUM>) which allows multiple transmitters to transmit simultaneously on the same resources a CRC and <NUM> zero tail bits used for the convolutional code.

As shown in both <FIG>, the sequence of disregard bits is located in the first and second U-SIG symbols; however, the CRC is computed as a function of all preceding bits which include both first U-SIG symbol and second U-SIG symbol, so the value of the CRC bits (located in the second U-SIG symbol) is also a function of the sequence of disregard bits located in the first U-SIG symbol.

11ax, a trigger frame contains <NUM> reserved bits and all <NUM> bits are set to '<NUM>'. The <NUM> reserved bits are copied to the second symbol of the HE-SIG-A field of a TB PPDU. In the current stage of <NUM>. 11be development, respective to a TB PPDU, there are <NUM> sequences of disregard bits in the first U-SIG symbol and <NUM> sequences of disregard bits in the second U-SIG symbol. All sequence of disregard bits are currently defined (in current stage of <NUM>. 11be development) as copied from the trigger frame (similar to <NUM>. 11ax operation). Maintaining the same design in 11be as it is in 11ax, the sequence of disregard bits copied from the trigger frame may be set to one.

Although a structure of the trigger frame is not presented in the present disclosure, the sequence of disregard bits in the trigger frame, and TB PPDU comprises contiguous binary bits '<NUM>' which can lead to high PAPR, and the performance of the U-SIG field for a TB PPDU will be impacted in consequence (e.g. with lower PAPR, the power amplifier backoff can be reduced, thereby increasing efficiency).

<FIG> shows a Complementary Cumulative Density Function (CCDF) of the PAPR of both U-SIG symbols for <NUM> BW (U-SIG-<NUM> means in <FIG> means the first symbol of the U-SIG field, and U-SIG-<NUM> means the second symbol of the U-SIG field). The sequence of disregard bits in the U-SIG symbols is assumed to be all ones. <FIG> shows the Complementary Cumulative Density Function (CCDF) of the PAPR of both U-SIG symbols, and compared with that of the data portion (assuming MCS <NUM> = BPSK rate ½) and with that of the Legacy SIG (L-SIG) field. As shown, the U-SIG PAPR is higher than that of the data by a large margin. It is also larger than that of the L-SIG field, especially the PAPR of the U-SIG-<NUM> symbol.

<FIG> shows a CCDF of the PAPR of both U-SIG symbols for <NUM> BW. It is shown that the effect shown in relation to <FIG> is consistent for other BW values and puncturing patterns. <FIG> shows a similar comparison with <NUM> BW. As shown therein, the PAPR of both U-SIG symbols also exceeds that of the L-SIG field and the data payload.

The current standard defines that pre-EHT fields that are duplicated on every <NUM> portion (e.g. L-SIG, U-SIG etc.) undergo per-<NUM> phase rotation in order to reduce the PAPR. However, as shown in <FIG> and <FIG>, the U-SIG PAPR is higher than both data and L-SIG, which means it is the limiting factor in terms of performance (it may define the power amplifier backoff).

It can be seen based on the simulation results from <FIG> and <FIG> that it is therefore of importance to reduce the PAPR of the U-SIG field.

In order to solve the problem above, the present disclosure provides a method and/or apparatus to reduce the PAPR of the TB PPDU, and in particular the PAPR of the U-SIG field.

Embodiments present in the present disclosure may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the embodiments.

The computer readable storage medium may be, for example, but is 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 of the foregoing.

A non-exhaustive list of more specific examples of the computer readable storage medium includes: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, and any suitable combination of the foregoing.

A network adapter card or network interface in each computing/processing device may receive computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.

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

In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of embodiments.

<FIG> 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 <NUM>. In some embodiments of the present disclosure, the processor <NUM> may be configured to control and manage one or more actions of the communication device, e.g. configured to execute a code for operating on a sequence of disregard bits to reduce the PAPR and/or to process the data transmitted and/or received in the AP. Optionally, the communication device may further include a memory <NUM> and a communications interface <NUM>. The processor <NUM>, the communications interface <NUM>, and the memory <NUM> may be connected to each other or may be connected to each other by using a bus <NUM>. The communications interface <NUM> is configured to support the communication device in performing communication, and the memory <NUM> is configured to store program code and data of the communication device. The processor <NUM> calls the code stored in the memory <NUM> to perform control and management. The memory <NUM> may or may not be coupled to the processor <NUM>.

The processor <NUM> 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 another programmable logical device, a transistor logical device, a hardware component, or any combination thereof. The processor <NUM> may implement or execute various example logical blocks, modules, and circuits described with reference to content disclosed in the present disclosure. Alternatively, the processor <NUM> may be a combination of processors implementing a computing function, for example, a combination of one or more microprocessors, or a combination of the digital signal processor and a microprocessor. The bus <NUM> may be a peripheral component interconnect (Peripheral Component Interconnect, PCI) bus, an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, or the like. The bus may be classified into an address bus, a data bus, a control bus, and the like.

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

The sequence of disregard bits in the present disclosure may be the predefined bits sequence in the prior art, e.g. present IEEE protocol. The sequence of disregard bits in some embodiments may be <NUM> or <NUM> bits and all bits are set as binary '<NUM>' in a TB PPDU. The sequence of disregard bits may refer to the <NUM>-bit sequence of disregard bits of the first U-SIG symbol in the TB PPDU, and/or to the <NUM>-bit sequence of disregard bits of the second U-SIG symbol in the TB PPDU. It should be noted that the sequence of disregard bits may include other number of binary bits and <NUM>-bit or <NUM>-bit is not a limitation in the present disclosure.

<FIG> shows a CCDF of the PAPR assuming a disregard bits sequence in which all bits are set to '<NUM>' except a single '<NUM>' in the edge of either U-SIG-<NUM> or U-SIG-<NUM>, assuming <NUM> without puncturing. In particular, the sequence '<NUM>' in U-SIG-<NUM> and '<NUM>' in U-SIG-<NUM> (so in total '<NUM>') is shown, which yields the lowest PAPR. <FIG> compares the CCDF of the PAPR of the all <NUM> case with that of the '<NUM>' sequence, with a single '<NUM>' in the end of the sequence, assuming <NUM> without puncturing. Since the first six values are identical in both sequences, the CCDF curves for U-SIG-<NUM> for both '<NUM>' and '<NUM>' is identical. For U-SIG-<NUM>, an improvement with the single '<NUM>' can be observed.

<FIG> shows a comparison between the CCDF of the PAPR of the all <NUM> case with that of the sequence of disregard bits with a single '<NUM>' at the end of the sequence, assuming <NUM> with puncturing pattern <NUM>. Again, since the first six values are identical in both sequences, the CCDF curve for U-SIG-<NUM> is identical. For U-SIG-<NUM>, an improvement with the single '<NUM>' can be observed.

<FIG> shows an example in which all bits are set to '<NUM>' except a single '<NUM>' in the edge of both U-SIG-<NUM> and U-SIG-<NUM>. In other words, using two values of '<NUM>' in the entire sequence, one '<NUM>' in U-SIG-<NUM> and one '<NUM>' in U-SIG-<NUM>.

In particular, the following sequences are shown in <FIG>:.

<FIG> shows a comparison between the CCDF of the PAPR of the all <NUM> case with that of the sequences suggested above, assuming <NUM> without puncturing, for U-SIG-<NUM>. As shown in <FIG>, there is an improvement in the PAPR.

<FIG> shows a comparison between the CCDF of the PAPR of the all <NUM> case with that of the same sequences as in <FIG>, assuming <NUM> without puncturing, for U-SIG-<NUM>. As shown in <FIG>, there is an improvement in the PAPR.

<FIG> shows the special user info field from an exemplary trigger frame of the present disclosure. In an example of the present disclosure, the field between B25 and B36 can be used as the field in which a disregard bits sequence is transmitted from an access point, which is received by communication devices and used as disregard bits sequence, such that a reduced PAPR is achieved.

<FIG> shows a definition of the 'U-SIG Disregard and Validate' subfield, and the copying of the disregard bits sequence into the U-SIG field.

<FIG> shows a workflow of a method for transmitting a physical layer protocol data unit, PPDU, in a communication device. The method comprises a step S1 of receiving a trigger frame in a first PPDU. Further, the method comprises a step S2 of obtaining a sequence of disregard bits of a universal signal, U-SIG, field in the first PPDU, wherein the sequence of disregard bits comprises at least one bit set to <NUM>. Also, the method further comprises a step S3 of copying the sequence of disregard bits into the U-SIG field of a second PPDU, and a step S4 of transmitting the second PPDU, wherein the second PPDU comprises the sequence of disregard bits.

<FIG> shows a workflow of a method for transmitting a physical layer protocol data unit, PPDU, in an access point. The method comprises a step S1 of setting a field of a trigger frame to a sequence comprising at least one <NUM>. The method further comprises a step S2 of transmitting the PPDU to one or more communication devices, wherein the PPDU comprises the field of the trigger frame, wherein the field of the trigger frame is configured to be copied by the one or more communication devices into disregard bits of a universal signal, U-SIG, sequence.

Any particular embodiment may include a plurality of "optional" features unless such features conflict.

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

It is appreciated that certain features of embodiments, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of embodiments, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment.

Claim 1:
A communication device for transmitting a physical layer protocol data unit, PPDU, to one or more receiving devices, wherein the communication device comprises:
a processor configured to:
receive a trigger frame in a first PPDU;
obtain a sequence of disregard bits of a universal signal, U-SIG, field in the first PPDU, by obtaining one of the sequences in the set {<NUM>, <NUM>, <NUM>}, wherein the sequence of disregard bits comprises at least one bit set to <NUM>; and
copy the sequence of disregard bits into the U-SIG field of a second PPDU; and
a transmitter configured to transmit the second PPDU, wherein the second PPDU comprises the sequence of disregard bits.