System and method for frequency domain copy mode transmission using orthogonal codes

Abstract

The invention relates to a system and method for frequency domain copy mode transmission using orthogonal codes. A system for providing copy mode orthogonal frequency division multiple access transmission while maintaining a relatively low peak-to-average power ratio is disclosed. Data to be transmitted are converted into symbols, and the symbols are copied to a certain number of resource units. A phase shift is applied to a number of symbols prior to transition to the time domain for transmission. The phase shift may be removed at the receiver prior to decoding the signal into transmitted data.

Description

[0001] Cross-referencing related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 644,190, filed May 8, 2024, and U.S. Provisional Patent Application No. 63 / 669,053, filed July 9, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of communications, and more particularly to systems and methods for frequency-domain copy mode transmission using orthogonal codes. Background Technology

[0004] This disclosure relates to improving communication reliability (e.g., in remote communications) by transmitting data in duplicate across different resource units of an orthogonal frequency domain multiple access (OFDMA) signal.

[0005] In certain applications, received signals in OFDMA communication networks can be degraded due to channel impairments (e.g., noise) or long travel distances. To mitigate data loss and / or the need for retransmission, the same data or symbols can be transmitted on multiple resource elements (RUs) of the OFDMA signal spectrum. For example, the RU52 subchannel in an OFDMA frame (e.g., for use in Wi-Fi networks) can be copied four times, or the RU26 subchannel in an OFDMA frame can be copied eight times. Copying symbols used for transmission can have a detrimental effect on signal characteristics because it causes the peaks of time-domain symbols to add constructively, resulting in an increased peak-to-average power ratio (PAPR). A higher PAPR requires a larger power backoff of the signal peaks and thus limits the maximum power transmitted. Summary of the Invention

[0006] One embodiment of this disclosure provides a system. The system includes one or more circuits configured to perform operations including: mapping a plurality of data symbols to magnitudes and phases to generate a plurality of symbols; applying a first set of corresponding phase shifts to the plurality of symbols to generate a first plurality of shifted symbols; applying a second set of corresponding phase shifts to the plurality of symbols to generate a second plurality of shifted symbols; generating a time-domain signal based on the first plurality of shifted symbols and the second plurality of shifted symbols; and transmitting the time-domain signal, wherein the first plurality of shifted symbols are assigned to a first plurality of subcarriers from a first resource unit and the second plurality of shifted symbols are assigned to a second plurality of subcarriers from a second resource unit.

[0007] Another embodiment of this disclosure provides a method. The method includes: mapping a plurality of data symbols to magnitudes and phases to generate a plurality of symbols; applying a first set of corresponding phase shifts to the plurality of symbols to generate a first plurality of shifted symbols; applying a second set of corresponding phase shifts to the plurality of symbols to generate a second plurality of shifted symbols; generating a time-domain signal based on the first plurality of shifted symbols and the second plurality of shifted symbols; and transmitting the time-domain signal, wherein the first plurality of shifted symbols are assigned to a first plurality of subcarriers from a first resource element and the second plurality of shifted symbols are assigned to a second plurality of subcarriers from a second resource element.

[0008] Another embodiment of this disclosure provides an apparatus. The apparatus includes one or more circuits configured to perform operations including: receiving a time-domain signal representing a plurality of data symbols; extracting a first plurality of shifted symbols from a subcarrier of a first resource unit and extracting a second plurality of shifted symbols from a subcarrier of a second resource unit; applying a first set of corresponding phase shifts to the first plurality of shifted symbols to generate a first plurality of symbols; applying a second set of corresponding phase shifts to the second plurality of shifted symbols to generate a second plurality of symbols; combining the first plurality of symbols and the second plurality of symbols to form a third plurality of symbols, wherein each of the third plurality of symbols is based at least on a first corresponding symbol in the first plurality of symbols and a second corresponding symbol in the second plurality of symbols; and mapping the magnitude and phase of each of the third plurality of symbols to generate the plurality of data symbols. Attached Figure Description

[0009] The various objectives, aspects, features, and advantages of this disclosure will become clearer and better understood through the detailed description taken in conjunction with the accompanying drawings, in which similar reference characters identify corresponding elements. In the drawings, similar reference numerals generally indicate identical, functionally similar, and / or structurally similar elements.

[0010] Figure 1A It is a block diagram depicting a network environment comprising one or more access points communicating with one or more devices or stations, according to some embodiments.

[0011] Figure 1B It is a block diagram depicting a computing device used in conjunction with the methods and systems described herein, according to some embodiments.

[0012] Figure 1C This is another block diagram depicting a computing device used in conjunction with the methods and systems described herein, according to some embodiments.

[0013] Figure 1D It is a graph of the cumulative distribution function of the peak-to-average power ratio of transmissions using different resource units assigned according to some embodiments.

[0014] Figure 2A This is a block diagram of a system for transmitting orthogonal frequency division multiple access signals using a replication mode phase shift circuit, according to some embodiments.

[0015] Figure 2B This is a block diagram of a system for receiving orthogonal frequency division multiple access signals using a replication mode phase shift circuit, according to some embodiments.

[0016] Figure 3A According to some embodiments Figure 2A A block diagram illustrating the operation of the replication mode phase shift circuit.

[0017] Figure 3B According to some embodiments Figure 2B A block diagram illustrating the operation of the replication mode phase shift circuit.

[0018] Figure 4A This is a flowchart, according to some embodiments, for transmitting orthogonal frequency division multiple access signals using phase shift.

[0019] Figure 4B This is a flowchart, according to some embodiments, for adding a phase shift to an orthogonal frequency division multiple access signal using a matrix stack.

[0020] Figure 5 This is a flowchart, according to some embodiments, for receiving an orthogonal frequency division multiple access signal with an added phase shift. Detailed Implementation

[0021] The following IEEE standards (including any draft versions of such standards) are hereby incorporated in their entirety hereto and form part of this disclosure for all purposes: the WiFi Alliance standards and the IEEE 802.11 standards, including but not limited to IEEE 802.11a. TM IEEE 802.11b TM IEEE 802.11g TM IEEE P802.11n TM IEEE P802.11ac TM ; and IEEE P802.11be TM To IEEE P802.11bn TM Standards. While this disclosure may refer to various aspects of these standards, it is in no way limited by them.

[0022] In some embodiments, a phase shift may be applied to symbols of a specific subcarrier in a replicated transmission. The phase shift can cause the symbols to no longer add constructively in the time domain, resulting in a favorable reduction in PAPR. In some embodiments, selecting a phase shift based on a specific Hadamard matrix can result in a PAPR similar to that of a non-replicated mode transmission.

[0023] Some embodiments relate to a system for transmitting remote communication by sending replicated symbol transmissions using a number of resource units. The system includes one or more circuits configured to perform operations. The operations include mapping a number of data symbols to magnitudes and phases to generate a number of symbols. The operations also include applying a first set of corresponding phase shifts to the symbols to generate a first set of shifted symbols. The operations further include applying a second set of corresponding phase shifts to the symbols to generate a second set of shifted symbols. The operations also include generating a time-domain signal based on the first set of shifted symbols and the second set of shifted symbols. The operations further include transmitting the time-domain signal. The first set of shifted symbols is assigned to a first number of subcarriers from a first resource unit, and the second set of shifted symbols is assigned to a second number of subcarriers from a second resource unit.

[0024] In some embodiments, a resource unit (RU) refers to a specific group of frequency modulations within an Orthogonal Frequency Division Multiple Access (OFDMA) communication channel. For example, a resource unit may refer to 48 subcarriers and 4 pilot subcarriers comprising a 52-frequency modulation resource unit for a 20 MHz bandwidth transmission. Resource units with different numbers of frequency modulations are also available, including, but not limited to, 26-frequency modulation resource units, 106-frequency modulation resource units, and 242-frequency modulation resource units. In some embodiments, a data symbol refers to a binary data value (e.g., '1' or '0') or a sequence thereof. For example, a data symbol may refer to a single '1' or '0' (e.g., in the case of binary phase shift keying modulation) or a data symbol may refer to any of the sequences '00', '01', '11', or '10' (e.g., in quadrature phase shift keying modulation). Data symbols represented by longer binary data sequences can be used in other modulation techniques, including various types of 8-phase shift keying (8-PSK) or quadrature amplitude modulation (QAM). In some embodiments, a symbol refers to the corresponding magnitude and phase of a binary sequence in the complex plane. For example, in binary phase shift keying (BPSK), a symbol may be 1 (e.g., 1 at 0°) or -1 (e.g., 1 at 180°); in quadrature phase shift keying (QPSK), a symbol may be 1 at 45°, 1 at 135°, 1 at 225°, or 1 at 315°. Symbols may contain magnitudes other than 1 (e.g., in QAM). In some embodiments, mapping data symbols to symbols means converting binary values ​​or sequences into corresponding magnitudes and phases. For example, mapping data symbols to symbols may refer to using a constellation diagram of the modulation scheme to determine the magnitude and phase corresponding to a particular binary sequence. Those skilled in the art will recognize that symbols (e.g., 1 at 45°, 1 at 135°, 1 at 225°, or 1 at 315°) may also use complex numbers (e.g., e^(-1 / 2)). jπ / 4 e j3π / 4 e -j3π / 4 e -jπ / 4 ) is used to represent this.

[0025] In some embodiments, applying a phase shift refers to changing the phase of a symbol. For example, a phase shift can be applied by multiplying the symbol by a number equal to 1 and having a phase equal to the number to be phase-shifted. In some embodiments, a shifted symbol can refer to a symbol that has been phase-shifted. For example, a shifted symbol can refer to a symbol after it has been correspondingly multiplied by a number equal to 1 and has a specific phase (e.g., a shift amount). In some embodiments, a time-domain signal can refer to a signal obtained by performing an inverse Fourier transform on symbols (or shifted symbols) at different subcarrier frequencies. For example, a time-domain signal (or time-domain symbol) can refer to the result of an inverse fast Fourier transform of subcarriers from four 52-band modulated resource units and represent the combination of all symbols on each subcarrier for a single transmission unit (e.g., 3.2 μs, 12.8 μs, or the amount of time a specific time-domain signal is transmitted).

[0026] In some embodiments, the operation further includes forming a symbol matrix and generating a matrix stack, the symbol matrix comprising a first column containing symbols and a second column containing symbols, the matrix stack comprising matrices arranged in a partitioned columnar format. The number of columns in the symbol matrix is ​​equal to the number of resource units used for transmitting duplicate symbols. The elements of the symbol matrix contain the corresponding symbols of the symbols, and the elements are defined by columns associated with resource units and rows associated with subcarriers of the resource units. A first set of corresponding phase shifts and a second set of corresponding phase shifts are applied by performing element-wise multiplication of the symbol matrix and the matrix stack.

[0027] In some embodiments, a symbol matrix refers to a matrix of symbols for a single transmission unit (e.g., a single time-domain symbol or time-domain signal). Each column of the symbol matrix may contain the symbol of a resource unit, and each row of the symbol matrix may represent a subcarrier within the resource unit. For example, a symbol matrix may refer to a 52×4 symbol matrix indicating four 52-frequency modulated resource units, or a symbol matrix may refer to a 26×8 symbol matrix indicating eight 26-frequency modulated resource units. A matrix stack refers to a column of partitioned matrices, where individual partitioned matrices are repeated to form multiple instances of the matrix. For example, a matrix stack may refer to a 52×4 matrix where a 4×4 matrix has been repeated 13 times and arranged in a column.

[0028] In some embodiments, the elements of the matrix have a value of 1.

[0029] In some embodiments, the rows of the matrix are orthogonal vectors.

[0030] In some embodiments, the matrix is ​​a cyclic Hadamard matrix.

[0031] In some embodiments, an element of a matrix or matrix stack with a magnitude of 1 refers to a value that, when multiplied by one of the signs, will only change the phase of the sign. For example, an element with a magnitude of 1 could refer to -1, 1, or e at a 45° angle.-jπ / 2 or e jπ / 2 The latter two will be considered by those skilled in the art as complex numbers with a magnitude of 1. In some embodiments, an orthogonal vector refers to a set of vectors in which the dot product of any pair of vectors is zero. For example, an orthogonal vector may refer to the set {[1 1] and [1 -1]}, because the sum of element-wise multiplications of two vectors (e.g., multiplication of elements with the same index or holding the same position) is zero. In some embodiments, a Hadamard matrix is ​​a square matrix with orthogonal rows and elements of 1 or -1. In some embodiments, a cyclic matrix is ​​a square matrix in which all rows contain the same element and each row is rotated one element to the right relative to the previous row. In some embodiments, a cyclic Hadamard matrix is ​​a square matrix that is both Hadamard and cyclic. For example, a Hadamard matrix may refer to matrix H4:

[0032]

[0033] A circular matrix can refer to matrix C4:

[0034]

[0035] Furthermore, the cyclic Hadamard matrix can be pointed to by matrix H. C4 :

[0036]

[0037] In some embodiments, the element in the matrix stack multiplied by the corresponding element in the symbol matrix corresponding to the pilot subcarrier is set to 1.

[0038] In some embodiments, the complex conjugate of the first column of the matrix stack is used to perform element-wise multiplication on each column of the matrix stack.

[0039] In some embodiments, a pilot subcarrier refers to a subcarrier in a resource element that has a known magnitude and phase, which can be used by transmitters and receivers in a synchronization network. For example, a pilot subcarrier may refer to one of four subcarriers in a 52-frequency modulation resource element that has a known magnitude and phase. In some embodiments, complex conjugate refers to a complex number whose phase angle has been multiplied by -1. For example, e jπ / 4 The complex conjugate can refer to e -jπ / 4 .

[0040] In some embodiments, the number of subcarriers in each of the resource units represented by the corresponding elements of the symbol matrix is ​​not divisible by the number of rows in the matrix. The matrix is ​​repeated to form a matrix stack having more stacked rows than the number of subcarriers in each of the resource units, and a certain number of the last rows of the matrix stack are removed from the matrix stack.

[0041] In some embodiments, the matrix has more columns than the symbolic matrix, and a certain number of the last columns of the matrix stack are removed from the matrix stack.

[0042] In some embodiments, phase shift is not applied to symbols assigned to pilot subcarriers.

[0043] In some embodiments, there are 52 subcarriers in each of the resource units and the symbols are copied to four resource units, or there are 26 subcarriers in each of the resource units and the symbols are copied to eight resource units.

[0044] Some embodiments relate to a method for transmitting remote communication by sending replicated symbol transmissions using a number of resource units. The method includes mapping a number of data symbols to magnitudes and phases to generate a number of symbols. The method further includes applying a first set of corresponding phase shifts to the symbols to generate a first set of shifted symbols. The method further includes applying a second set of corresponding phase shifts to the symbols to generate a second set of shifted symbols. The method further includes generating a time-domain signal based on the first set of shifted symbols and the second set of shifted symbols. The method further includes transmitting the time-domain signal. The first set of shifted symbols is assigned to a first number of subcarriers from a first resource unit, and the second set of shifted symbols is assigned to a second number of subcarriers from a second resource unit.

[0045] In some embodiments, the method further includes forming a symbol matrix comprising a first column of symbols and a second column of symbols, and generating a matrix stack comprising matrices arranged in a partitioned columnar format. The number of columns in the symbol matrix is ​​equal to the number of resource units used for transmitting duplicate symbols. The elements of the symbol matrix comprise the corresponding symbols of the symbols, and the elements are defined by columns associated with resource units and rows associated with subcarriers of the resource units. The first set of corresponding phase shifts and the second set of corresponding phase shifts are applied by performing element-wise multiplication of the symbol matrix and the matrix stack.

[0046] In some embodiments, the elements of the matrix have a value of 1.

[0047] In some embodiments, the matrix is ​​a cyclic Hadamard matrix.

[0048] In some embodiments, the element in the matrix stack multiplied by the corresponding element in the symbol matrix corresponding to the pilot subcarrier is set to 1.

[0049] In some embodiments, the complex conjugate of the first column of the matrix stack is used to perform element-wise multiplication on each column of the matrix stack.

[0050] Some embodiments relate to a system for receiving remote communications using a number of resource units and employing duplicate symbol transmission. The system includes one or more circuits configured to perform operations. The operations include receiving a time-domain signal representing a number of data symbols. The operations include extracting a first set of shifted symbols from a subcarrier of a first resource unit and a second set of shifted symbols from a subcarrier of a second resource unit. The operations include applying a first set of corresponding phase shifts to the first set of shifted symbols to generate a first set of symbols. The operations also include applying a second set of corresponding phase shifts to the second set of shifted symbols to generate a second set of symbols. The operations further include combining the first set of symbols and the second set of symbols to form a third set of symbols. Each symbol in the third set of symbols depends on a first corresponding symbol in the first set of symbols and a second corresponding symbol in the second set of symbols. The magnitude and phase of each of the symbols in the third set are mapped to generate a set of data symbols.

[0051] In some embodiments, the operation further includes forming a symbol matrix comprising a first column of a first set of shifted symbols and a second column of a second set of shifted symbols, and generating a matrix stack comprising matrices arranged in a partitioned columnar format. The number of columns in the symbol matrix is ​​equal to the number of resource units used to transmit duplicate symbol transmissions. Elements of the symbol matrix comprise corresponding shifted symbols from either the first or second set of shifted symbols, defined by columns associated with resource units and rows associated with the subcarriers of the resource units. The first and second set of corresponding phase shifts are applied by performing element-wise multiplication of the symbol matrix and the matrix stack.

[0052] In some embodiments, the matrix is ​​an orthogonal matrix.

[0053] In some embodiments, the matrix is ​​a cyclic Hadamard matrix.

[0054] In some embodiments, extracting symbols from a subcarrier of a resource unit refers to determining them within the signal's spectrum. For example, extracting symbols from a subcarrier may refer to performing an FFT on the received signal. In some embodiments, combining symbols refers to generating a single set of symbols or data symbols from replicated symbols or data symbols. For example, combining symbols may refer to performing vector averaging across received replicated symbols or using the most frequent data symbol across received replicated data symbols. In some embodiments, an orthogonal matrix refers to a matrix whose rows are orthogonal vectors. For example, an orthogonal matrix may refer to a matrix... Or the Hadamard matrix H4.

[0055] This overview is illustrative only and is not intended to be limiting in any way. Other aspects, inventive features, and advantages of the apparatus or process described herein will become clearer from the detailed description set forth herein, taken in conjunction with the accompanying drawings, in which similar reference numerals refer to similar elements.

[0056] Communication Network

[0057] Before discussing specific embodiments, it may be helpful to describe various aspects of the operating environment and associated system components (e.g., hardware elements) in conjunction with the methods and systems described herein. References Figure 1A This describes an embodiment of a network environment. In short, the network environment includes a wireless communication system comprising one or more access points (APs) or network devices 106, one or more stations or wireless communication devices 102, and network hardware components or network hardware 192. For example, wireless communication device 102 may include a laptop computer, tablet computer, personal computer, and / or cellular telephone device. (See reference...) Figure 1B and 1C More detailed descriptions are provided for embodiments of each station or wireless communication device 102 and AP or network device 106. In one embodiment, the network environment may be an ad hoc network environment, an infrastructure wireless network environment, a sub-network environment, etc. Network device 106 or AP may be operatively coupled to network hardware 192 via a local area network (LAN) connection. In some embodiments, network device 106 is a 5G base station. Network hardware 192 may include routers, gateways, switches, bridges, modems, system controllers, appliances, etc., providing LAN connectivity for the communication system. Each of network device 106 or AP may have an associated antenna or antenna array to communicate with wireless communication devices in its area. Wireless communication device 102 may register with a specific network device 106 or AP to receive services from the communication system (e.g., via SU-MIMO or MU-MIMO configuration). For direct connections (e.g., point-to-point communication), some wireless communication devices may communicate directly via an assigned channel and communication protocol. Some wireless communication devices 102 may be mobile or relatively stationary relative to network device 106 or AP.

[0058] In some embodiments, network device 106 or AP includes means or modules (comprising a combination of hardware and software) that allow wireless communication device 102 to connect to a wired network using Wireless Fidelity (WiFi) or other standards. Network device 106 or AP may sometimes be referred to as a Wireless Access Point (WAP). Network device 106 or AP may be implemented (e.g., configured, designed, and / or built) for operation in a Wireless Local Area Network (WLAN). In some embodiments, network device 106 or AP may be connected as a standalone device to a router (e.g., via a wired network). In other embodiments, network device 106 or AP may be a component of a router. Network device 106 or AP may provide network access to multiple devices. For example, network device 106 or AP may connect to a wired Ethernet connection and use a radio frequency link to provide wireless connectivity to other devices 102 to utilize the wired connection. Network device 106 or AP may be implemented to support standards for transmitting and receiving data using one or more radio frequencies. Those standards and the frequencies they use may be defined by IEEE (e.g., the IEEE 802.11 standard). Network device 106 or AP can be configured and / or used to support public Internet hotspots and / or extend the Wi-Fi signal range of a network over a network.

[0059] In some embodiments, the access point or network device 106 may be used (e.g., in a home, vehicle, or building) for a wireless network (e.g., IEEE 802.11, Bluetooth, ZigBee, any other type of radio frequency-based network protocol, and / or variations thereof). Each of the wireless communication devices 102 may include a built-in radio and / or be coupled to a radio. Such wireless communication devices 102 and / or access point or network device 106 may operate according to various aspects of the present disclosure presented herein to enhance performance, reduce cost and / or size, and / or enhance broadband applications. Each wireless communication device 102 may have the capability to act as a client node seeking access to resources (e.g., data and connections to networked nodes such as servers) via one or more access points or network devices 106.

[0060] The network connection may include any type and / or form of network and may include any of the following: point-to-point network, broadcast network, telecommunications network, data communication network, computer network. The network topology may be a bus, star, or ring network topology. The network may be any such network topology known to those skilled in the art capable of supporting the operations described herein. In some embodiments, different types of data may be transmitted via different protocols. In other embodiments, the same type of data may be transmitted via different protocols.

[0061] The communication device 102 and the access point or network device 106 may be deployed as any type and form of computing device (e.g., a computer, network device or appliance capable of communicating and performing the operations described herein on any type and form of network) and / or executed on said any type and form of computing device. Figure 1B and 1C A block diagram depicting a computing device 100 for implementing embodiments of wireless communication device 102 or network device 106. (See diagram for reference.) Figure 1B and 1C As shown, each computing device 100 includes a processor 121 (e.g., a central processing unit) and a main memory unit 122. Figure 1B As shown, the computing device 100 may include a storage device 128, a mounting device 116, a network interface 118, an I / O controller 123, display devices 124a to 124n, a keyboard 126, and a pointing device 127 (e.g., a mouse). The storage device 128 may include an operating system and / or software. Figure 1C As shown, each computing device 100 may also include additional optional components such as memory port 103, bridge 170, one or more input / output devices 130a to 130n, and cache memory 140 that communicates with the central processing unit or processor 121.

[0062] The central processing unit or processor 121 is any logical circuit system that responds to and processes instructions fetched from main memory unit 122. In many embodiments, the central processing unit or processor 121 is provided by a microprocessor unit, such as a microprocessor unit manufactured by Intel Corporation of Santa Clara, California; a microprocessor unit manufactured by International Business Machines of White Plains, New York; or a microprocessor unit manufactured by Advanced Micro Devices of Sunnyvale, California. The computing device 100 may be based on any of these processors, or any other processor capable of operating as described herein.

[0063] Main memory unit 122 may be one or more memory chips capable of storing data and allowing the microprocessor or processor 121 to directly access any memory location, such as any type or variant of static random access memory (SRAM), dynamic random access memory (DRAM), ferroelectric RAM (FRAM), NAND flash memory, NOR flash memory, and solid-state drive (SSD). Main memory unit 122 may be based on any of the memory chips described above, or any other available memory chips capable of operating as described herein. Figure 1B In the embodiment shown, the processor 121 communicates with the main memory unit 122 via the system bus 150 (described in more detail below). Figure 1C An embodiment of the computing device 100 is depicted, wherein the processor communicates directly with the main memory unit 122 via memory port 103. For example, in Figure 1C In this context, the main memory unit 122 can be DRDRAM.

[0064] Figure 1C An embodiment is depicted in which the main processor 121 communicates directly with the cache memory 140 via a secondary bus (sometimes referred to as the back-side bus). In other embodiments, the main processor 121 communicates with the cache memory 140 using a system bus 150. The cache memory 140 typically has a faster response time than the main memory cell 122 and is provided by, for example, SRAM, BSRAM, or EDRAM. Figure 1C In the embodiments shown, processor 121 communicates with various I / O devices 130 via local system bus 150. Various buses can be used to connect the central processing unit or processor 121 to any of the I / O devices 130, such as VESA VL bus, ISA bus, EISA bus, Micro Channel Architecture (MCA) bus, PCI bus, PCI-X bus, high-speed PCI bus, or NuBus. In embodiments where the I / O device is a video display 124, processor 121 can use an Advanced Graphics Port (AGP) to communicate with the display 124. Figure 1C An embodiment of a computer or computer system 100 is depicted, wherein the main processor 121 can communicate directly with the I / O device 130b, for example, via HYPERTRANSPORT, RAPIDIO, or INFINIBAND communication technologies. Figure 1C An embodiment in which a local bus is mixed with direct communication is also depicted: the processor 121 communicates with the I / O device 130a using the local interconnect bus, while simultaneously communicating directly with the I / O device 130b.

[0065] The computing device 100 may contain a variety of I / O devices 130a to 130n. Input devices include keyboards, mice, trackpads, trackballs, microphones, dial pads, touchpads, touchscreens, and drawing tablets. Output devices include video displays, speakers, inkjet printers, laser printers, projectors, and dye-to-sublimation printers. The I / O devices can be controlled by the I / O controller 123, such as... Figure 1B As shown in the diagram. The I / O controller can control one or more I / O devices, such as keyboard 126 and pointing device 127 (e.g., mouse or light pen). Additionally, the I / O devices can provide storage and / or mounting media for the computing device 100. In other embodiments, the computing device 100 may provide USB connectivity (not shown) to receive handheld USB storage devices, such as the USB flash drive series manufactured by Twintech Industry, Inc. of Los Alamitos, California.

[0066] Refer again Figure 1B The computing device 100 may support any suitable installation device 116, such as a disk drive, CD-ROM drive, CD-R / RW drive, DVD-ROM drive, flash memory drive, tape drive of various formats, USB device, hard disk drive, network interface, or any other device suitable for installing software and programs. The computing device 100 may further include storage devices for storing the operating system and other related software, as well as for storing application software programs (e.g., any program or software 120 used to implement (e.g., configured and / or designed for) the systems and methods described herein), such as one or more hard disk drives or a standalone redundant disk array. Optionally, any of the installation devices 116 may also be used as storage devices. Additionally, the operating system and software may be run from bootable media.

[0067] In addition, the computing device 100 may include a network interface 118 to access a network via a variety of connections, including but not limited to standard telephone lines, LAN or WAN links (e.g., 802.11, T1, T3, 56kb, X.25, SNA, DECNET), broadband connections (e.g., ISDN, Frame Relay, ATM, Gigabit Ethernet, Ethernet-over-SONET), wireless connections, or any or a combination of all of the above. A variety of communication protocols can be used to establish a connection (e.g., TCP / IP, IPX, SPX, NetBIOS, Ethernet, ARCNET, SONET, SDH, Fiber Distributed Data Interface (FDDI), RS232, IEEE 802.11, IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, IEEE 802.11ac, IEEE 802.11ad, CDMA, GSM, WiMax, and Direct Asynchronous Connection). In one embodiment, computing device 100 communicates with other computing devices 100' via any type and / or form of gateway or tunneling protocol (e.g., Secure Sockets Layer (SSL) or Transport Layer Security (TLS)). Network interface 118 may include a built-in network adapter, network interface card, PCMCIA network card, card bus network adapter, wireless network adapter, USB network adapter, modem, or any other device suitable for interfacing computing device 100 to any type of network capable of communication and performing the operations described herein.

[0068] In some embodiments, computing device 100 may include or be connected to one or more display devices 124a to 124n. Thus, any of the I / O devices 130a to 130n and / or the I / O controller 123 may include any type and / or form of suitable hardware, software, or a combination of hardware and software to support, enable, or provide connectivity and use of the display devices 124a to 124n by computing device 100. For example, computing device 100 may include any type and / or form of video adapter, video card, driver, and / or library for interfacing, communicating, connecting, or otherwise using the display devices 124a to 124n. In one embodiment, a video adapter may include multiple connectors to interfacing with the display devices 124a to 124n. In other embodiments, computing device 100 may include multiple video adapters, each connected to the display devices 124a to 124n. In some embodiments, any portion of the operating system of computing device 100 may be configured to use multiple display devices 124a to 124n. In other embodiments, I / O device 130 may be a bridge between system bus 150 and external communication buses such as USB bus, Apple Desktop bus, RS-232 serial connection, SCSI bus, FireWire bus, FireWire 800 bus, Ethernet bus, AppleTalk bus, Gigabit Ethernet bus, Asynchronous Transfer Mode bus, Fibre Channel bus, Fibre Bus, Serial Attached Small Computer System Interface bus, USB connection, or HDMI bus.

[0069] Figure 1B and 1CThe computing device 100 of the type described herein can operate under the control of an operating system that controls task scheduling and access to system resources. The computing device 100 can run any operating system, such as any version of Microsoft Windows, different versions of Unix and Linux, any version of MAC OS for Macintosh computers, any embedded operating system, any real-time operating system, any open-source operating system, any proprietary operating system, any operating system for mobile computing devices, or any other operating system capable of running on the computing device and performing the operations described herein. Typical operating systems include, but are not limited to: Android, produced by Google Inc.; Windows 7, 8, and 10, produced by Microsoft Corporation of Redmond, Washington; MAC OS, produced by Apple Computer of Cupertino, California; WebOS, produced by Research In Motion (RIM); OS / 2, produced by International Business Machines of Armonk, New York; and Linux, a free operating system released by Caldera Corp. of Salt Lake City, Utah, or any type and / or form of Unix operating system, and others.

[0070] The computer system or computing device 100 may be any workstation, telephone, desktop computer, laptop or notebook computer, server, handheld computer, mobile phone or other portable telecommunications device, media playback device, gaming system, mobile computing device, or any other type and / or form of computing, telecommunications, or media device capable of communication. In some embodiments, the computing device 100 may have a different processor, operating system, and input device consistent with the device described herein. For example, in one embodiment, the computing device 100 is a smartphone, mobile device, tablet computer, or personal digital assistant. Furthermore, the computing device 100 may be any workstation, desktop computer, laptop or notebook computer, server, handheld computer, mobile phone, any other computer, or other form of computing or telecommunications device capable of communication and having sufficient processor power and memory capacity to perform the operations described herein.

[0071] In some embodiments, fidelity for long-distance transmission is improved by replicating the transmission across multiple resource units. For example, the same symbols can be transmitted, and errors can be corrected at the receiver side by comparing subcarriers on multiple resource units using the same symbols. While replicated transmission allows for receiver error correction, it can have a detrimental effect on the peak-to-average power ratio (PAPR) because replicating symbols can cause the peaks of the time-domain signal transmission to add constructively together. (Reference) Figure 1D Figure 160 illustrates the impact of copy mode transmission on PAPR. Trajectory 162 represents the cumulative probability distribution function of a transmission using 242 frequency modulation resource units (e.g., resource units where each frequency modulation carries a unique symbol) and is used as a reference for PAPR. Using trajectory 162, a median PAPR transmission of 242 frequency modulation resource units can be seen to be slightly greater than 7.5 dB. Trajectory 164 represents the cumulative probability distribution function of a transmission copied over four 52 frequency modulation resource units. Trajectory 164 shows a median PAPR of approximately 11 dB for this transmission. Therefore, copy mode transmission has resulted in an increase in PAPR of approximately 3.5 dB. A larger PAPR can limit maximum transmission power and lead to a decrease in signal-to-noise ratio at the receiver. In some embodiments, using the systems and methods described herein, the PAPR of copy mode transmission can be reduced to the PAPR represented by trajectory 166, which represents a reduction of more than 3.5 dB.

[0072] Transmission and reception circuit system

[0073] Figure 2A This is an illustrative block diagram of the circuitry and interconnections of a system configured to perform replicated mode transmission of Orthogonal Frequency Division Multiple Access (OFDMA) signals with a reduced PAPR. For example, the circuitry may consist of components connected to... Figure 1A The circuitry can be implemented using any network shown or any device that communicates with the network. For example, the circuitry can be implemented within network device 106 and used to communicate with any user device 102. In some embodiments, the circuitry can be implemented using one or more memory devices and one or more processors. In some embodiments, the circuitry can be implemented using application-specific integrated circuits (ASICs) or system-on-a-chip integrated circuits.

[0074] The processor may be a general-purpose or special-purpose processor, an application-specific integrated circuit (ASIC), one or more field-programmable gate arrays (FPGAs), a set of processing components, or other suitable processing components. The processor may be configured to execute computer code and / or instructions stored in memory or received from other computer-readable media (e.g., CD-ROM, network storage device, remote server, etc.). The processor may be configured in various computer architectures, such as a graphics processing unit (GPU), a distributed computing architecture, a cloud server architecture, a client-server architecture, or various combinations thereof. One or more first processors may be implemented by a first device, such as an edge device, and one or more second processors may be implemented by a second device, such as a server or other device communicatively coupled to the first device and which may have larger processor and / or memory resources.

[0075] The memory may include one or more means (e.g., memory cells, memory devices, storage devices, etc.) for storing data and / or computer code to perform and / or facilitate the various processes described herein. The memory may include random access memory (RAM), read-only memory (ROM), hard disk storage devices, temporary storage devices, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and / or computer instructions. The memory may include database components, object code components, scripting components, or any other type of information structure and information structures described herein for supporting various activities. The memory may be communicatively connected to a processor and may contain computer code for performing (e.g., via a processor) one or more processes described herein.

[0076] refer to Figure 2A According to some embodiments, the Orthogonal Frequency Division Multiple Access (OFDMA) transmission system 200 is shown as comprising several interconnected circuits. The OFDMA transmission system 200 may include an OFDMA transmission circuit 202, a resource unit selection circuit 204, a subcarrier assignment circuit 206, a symbol mapping circuit 208, a replication mode phase shift circuit 210, an inverse fast Fourier transform (inverse FFT) circuit 212, an adjustment circuit 214, and a modulation circuit 216. It should be understood that in some embodiments, functionality can be distributed in different ways across any number of circuits. For example, the functionality of the replication mode phase shift circuit 210 and the inverse fast Fourier transform (inverse FFT) circuit 212 may be performed in a single circuit.

[0077] OFDMA transmission circuitry 202 can be configured to control the timing and flow of data through other circuitry systems of OFDMA transmission system 200. For example, OFDMA transmission circuitry 202 can cause modules or circuits to execute in a specific order to perform the functions of OFDMA transmission system 200. In some embodiments, OFDMA transmission circuitry 202 can route information and / or the outputs of other modules that depend on or use the information as input. Instructions, modules, memory portions, etc., described as configured to perform a function (or described as performing a function) may contain embodiments in which modules are configured to cause (or are causing) the execution of a function. Similarly, instructions, modules, memory portions, etc., described as configured to cause (or described as causing) the execution of a function may contain embodiments in which modules are configured to perform (or are performing) a function.

[0078] Resource element selection circuit 204 can be configured to receive an indication of replication mode. For example, resource element selection circuit 204 can receive an indication of RU26-DUP8, thereby indicating the replication of 26 frequency modulation data symbol groups across 8 resource elements; or, as another example, resource element selection circuit 204 can receive an indication of RU52-DUP4, thereby indicating the replication of 52 frequency modulation data symbol groups across 4 resource elements. Resource element selection circuit 204 can pass the selection of resource elements (e.g., transmission, propagation, etc.) to subcarrier assignment circuit 206.

[0079] Given a resource unit assignment, subcarrier assignment circuit 206 can receive data to be transmitted and associate data symbols with appropriate subcarriers. Subcarrier assignment circuit 206 can be configured to decompose the data stream into data symbols of length suitable for a modulation technique. For example, each binary data (e.g., an individual '1' or '0') can be assigned to a subcarrier in BPSK. In some embodiments, a longer sequence of binary data can be assigned to a single subcarrier (e.g., a four-bit sequence can be assigned to a subcarrier in 16-QAM). The binary sequence (e.g., data symbol) assigned to an individual subcarrier can be passed (e.g., transmitted, propagated, etc.) to symbol mapping circuit 208.

[0080] Subcarrier assignment circuit 206 can be configured to maintain (e.g., store, create, etc.) the distribution of subcarriers associated with a specific resource unit. For example, in a 52-band frequency modulation resource unit scheme, 48 data symbols can be assigned to subcarrier indices -121 to -70, skipping 4 pilot symbols. If the data will be copied 4 times, then for resource unit 2, the same data symbols can be additionally assigned to subcarriers -68 to -17; for resource unit 3, the same data symbols can be additionally assigned to subcarriers 17 to 68; and for resource unit 4, the same data symbols can be additionally assigned to subcarriers 70 to 121.

[0081] Symbol mapping circuit 208 can be configured to receive data symbols and convert each data symbol into a symbol containing a magnitude and phase (e.g., represented by a complex number). Symbol mapping circuit 208 can be configured to use a constellation diagram to map data symbols to corresponding magnitudes and phases. For example, in BPSK, symbol mapping circuit 208 can map binary '1' to symbol 1 (e.g., magnitude 1 and phase angle 0°) and binary '0' to symbol -1 (e.g., magnitude 1 and phase angle 180°). In some embodiments, other mappings can be used. For example, in quadrature phase shift keying, data symbols '11', '01', '00', and '10' can be mapped to e respectively. jπ / 4 e j3π / 4 e -j3π / 4 e -jπ / 4 In some embodiments, data symbols may also be mapped to symbols of different magnitudes. For example, 16-QAM may map '0001' to a symbol with an amplitude of 0.75 and a phase angle of 161.6°. The symbol associated with each subcarrier can then be passed to the replication mode phase shift circuit 210.

[0082] The replication-mode phase-shifting circuit 210 can be configured to apply a known phase shift to symbols assigned to a number of subcarriers. Performing a phase shift on symbols of a specific subcarrier advantageously limits the phase-length addition of the subcarriers in the time domain and produces an improved PAPR. For example, the replication-mode phase-shifting circuit 210 can be configured to always shift the symbol associated with the subcarrier index (e.g., frequency modulation index) -121, possibly always by 180°. The known phase shift can be removed by the receiver before the received symbol is mapped back to a data symbol. In some embodiments, the receiver may operate based on a change in phase rather than a specific phase angle, so explicit removal of the phase shift by the receiver may not be necessary.

[0083] In some embodiments, the replication mode phase shift circuit 210 may be configured to maintain (e.g., store, create, etc.) the mapping between different subcarrier indices and corresponding phase shifts. For example, subcarrier indices (e.g., each index associated with a different frequency) -121 to -70, 68 to -17, 17 to 68, and 70 to 121 may be assigned to replication resource units 1, 2, 3, and 4, respectively, and the replication mode phase shift circuit 210 may apply a 180° phase shift to every fourth subcarrier index, starting from the first index in resource unit 1, the second index in resource unit 2, the third index in resource unit 3, and the fourth index in resource unit 4.

[0084] The replication-mode phase shift circuit 210 can maintain any mapping from the subcarrier index to the corresponding phase shift; however, some phase shift strategies can improve the final PAPR of the transmission. In some embodiments, no phase shift is applied to the pilot signal to avoid necessary changes to anything in the synchronization circuit system based on the known subcarrier symbol. In some embodiments, the phase shift may not be 180°. For example, the phase shift may be 90° or any other phase shift that causes a decrease in PAPR. In some embodiments, the Hadamard matrix can be used to find the phase shift, as will be referenced herein. Figure 3A and 3B As described. In some embodiments, phase shift is applied by multiplying the sign by a complex number having a non-zero phase angle.

[0085] The inverse Fast Fourier Transform (Inverse FFT) circuit 212 can be configured to receive symbols associated with their respective subcarrier frequencies (some of which may have been shifted by the replication mode phase shift circuit 210) and perform an inverse Fourier transform (e.g., inverse FFT) to generate a time-domain signal at the baseband frequency. The time-domain signal associated with the current data symbol can last for a specific duration. In some embodiments, the duration of the time-domain signal depends on the frequency interval of the subcarrier frequency modulation. For example, the time-domain signal may have a period of 12.8 μs related to the reciprocal of the 78.125 kHz subcarrier interval.

[0086] The time-domain signal can be delivered to conditioning circuit 214. In some embodiments, conditioning circuit 214 may perform additional processing to prepare the time-domain signal for transmission. Conditioning circuit 214 may be configured to buffer several time-domain signals, allowing the signal stream to be transmitted without waiting for previous circuitry to complete its calculations. In some embodiments, a guard period (e.g., a period of time when no useful data is transmitted) may also be added before and after the duration of the time-domain signal to prevent time-domain signals from one set of data symbols (e.g., data assigned to a subcarrier in subcarrier assignment circuit 206 within a single iteration) from interfering with time-domain signals from another set of data symbols. The guard period may be particularly important when multipath interference causes different time delays between time-domain signals.

[0087] The regulated time-domain signal leaving the conditioning circuit 214 can be passed to the modulation circuit 216. The modulation circuit 216 can be configured to multiply the time-domain signal by a carrier frequency (e.g., one of a channel in the 2.4 GHz band or the 5 GHz band) before transmitting the time-domain signal.

[0088] Figure 2B This is an illustrative block diagram of the circuitry and interconnections of a system configured to perform replicated mode reception of Orthogonal Frequency Division Multiple Access (OFDMA) signals, embodied as an OFDMA receiver system 250. The circuitry of the OFDMA receiver system 250 may be implemented within a network device 106 and used to communicate with any user device 102, and may use components similar to those described for the OFDMA transmission system 200 (e.g., processors, ASICs, system-on-a-chip).

[0089] In some embodiments, the OFDMA receiver system 250 includes OFDMA receiver circuitry 252, demodulation circuitry 256, FFT circuitry 258, replication mode phase shift circuitry 260, symbol mapping circuitry 262, comparator circuitry 264, and data streaming circuitry 266. It should be understood that in some embodiments, functionality can be distributed across any number of circuits in different ways. For example, the functionality of replication mode phase shift circuitry 260 and Fast Fourier Transform (FFT) circuitry 258 can be performed in a single circuit. The circuitry of the OFDMA receiver system 250 may include a processor that executes instructions stored in a memory device, an ASIC, or a system-on-a-chip architecture, as previously described.

[0090] OFDMA receiver circuit 252 has similar functionality to OFDMA transmitter circuitry, but the sequence is inverted to receive time-domain signals at the carrier frequency and convert them into a data stream. OFDMA receiver circuit 252 can be configured to control the timing and flow of data through other circuitry systems. For example, OFDMA receiver circuit 252 can cause modules or circuits to execute in a specific order to perform the functions of OFDMA receiver system 250. In some embodiments, OFDMA receiver circuit 252 can route information and / or the outputs of other modules that depend on or use that information as input.

[0091] The demodulation circuit 256 can be configured to receive time-domain signals (e.g., from antenna and amplifier circuitry) and convert the time-domain signals into digital signals at baseband frequencies. For example, the demodulation circuit 256 may include both a demodulation circuitry system and an analog-to-digital converter to convert the received analog signals into digital signals for processing by other circuitry of the OFDMA receiver system 250.

[0092] Demodulation circuit 256 can pass the baseband time-domain signal to FFT circuit 258. The FFT circuit can be configured to convert the time period of the time-domain signal (e.g., 12.8 μs, or the time frequency corresponding to the reciprocal of the subcarrier frequency interval) back to the number of phase-shifted symbols at various subcarrier frequencies. For example, the output of FFT circuit 258 may contain a phase-shifted signal (e.g., a phase shift associated with a known phase shift applied by the transmitter) for each subcarrier index (e.g., frequency).

[0093] In some embodiments, the receiver's replication mode phase shift circuit 260 applies a phase shift to cancel (e.g., reverse, cancel) the phase shift applied by the transmitter's replication mode phase shift circuit 210. Similar to the transmitter, the receiver's replication mode phase shift circuit 260 can be configured to apply a known phase shift to symbols assigned to a number of subcarriers. For example, the known phase shift can be specified to cancel (e.g., eliminate, remove, etc.) the phase shift applied by the transmitter. By using the replication mode phase shift circuit 260 to cancel the phase shift applied by the transmitter, subcarriers transmitting with the same data symbols again have the same symbols (e.g., assuming no interference or other channel effects cause errors).

[0094] In some embodiments, the phase shift applied by the replication mode phase shift circuit 210 is always 180°. A subsequent 180° phase shift performed by the replication mode phase shift circuit 260 will eliminate the original 180° phase shift. Therefore, in scenarios where the transmitter only adds a 180° phase shift, the transmitter and receiver can apply the same phase shift to the same carrier frequency. In some embodiments, the transmitter applies a general phase shift and the receiver can perform the same amount but in the opposite direction of a phase shift to eliminate the original phase shift. The phase shifts applied to individual subcarriers in different replication transmission modes can be pre-arranged (e.g., configured in the software or firmware of the transmitter and receiver), or the transmitter can pass a mapping between the subcarrier frequency and the phase shift to the receiver (e.g., using non-shift communication) and then continue to use the passed phase shift mapping in future communications (e.g., until the transmission ends or a predetermined time expires).

[0095] In some embodiments, a phase shift is applied by multiplying the symbol by a complex number having a non-zero phase angle. Specifically, if the transmitter multiplies the symbol by a complex number to apply a phase shift, the receiver can multiply the received symbol by the complex conjugate of the complex number to cancel the phase shift. In some embodiments, a change in phase is used to indicate the symbol (e.g., to replace a specific phase) and it may not be necessary to cancel the phase shift added by the transmitter.

[0096] In some embodiments, symbols for each subcarrier index are passed from the replication mode phase shift circuit 260 to the symbol mapping circuit 262 and the comparison circuit 264. The symbol mapping circuit 262 and the comparison circuit 264 can be applied in any order, depending on the technology used. In some embodiments, the symbol mapping circuit 262 is analogous to the symbol mapping circuit of a transmitter. The symbol mapping circuit 262 can be configured to convert symbols into corresponding data symbols using a constellation diagram of the current modulation scheme. The comparison circuit 264 corrects any mismatches between symbols associated with subcarriers that should receive the same data in a given replication mode, based on the replication mode. Comparisons can be performed on binary data (e.g., after the symbol mapping circuit 262) or on symbols (e.g., before the symbol mapping circuit).

[0097] Symbols copied to multiple subcarriers can be combined after they are received. For example, comparison circuit 264 can compare data symbols spanning subcarriers assigned as copies of each other (e.g., a specific carrier index for each resource unit) and determine the combined data symbol based on a majority vote (e.g., the data symbol with the most instances is the combined symbol). In some embodiments, comparison circuit 264 can find an average symbol (e.g., by taking the vector average of all symbols to be combined) and determine the closest symbol on the constellation diagram.

[0098] Data associated with a single resource unit (e.g., a previously combined copy) can be passed to data streaming circuitry 266. Data streaming circuitry 266 can be configured to sequence data on the subcarriers of the resource unit into a single stream, thereby completing the reception of time-domain signals and decoding the time-domain signals into useful binary data.

[0099] refer to Figure 3A The operation of the replication mode phase shift circuit 210 is illustrated according to some embodiments. For example, Figure 3AThis demonstrates the application of phase shift by performing element-wise matrix multiplication on the replicated symbols. Consider a resource unit with N frequency moduli (e.g., 26 frequency moduli, 52 frequency moduli, etc.). Symbols associated with data for each subcarrier (e.g., frequency modulus) can be arranged in a single symbol column 302 (e.g., after the data symbols have been converted to symbols). Symbol column 302 can be replicated D times to fill D resource units. Symbol matrix 311 may contain replicated columns 304, 306, 308 to 310, as shown below. Figure 3A As shown in the figure. The size of the symbol matrix can be N×D.

[0100] Additionally, a matrix 314 containing at least D columns (e.g., represented by a square matrix H) can be arranged in a segmented columnar form (e.g., one matrix H sits on top of the next matrix H, and so on) to form a matrix stack 316. In some embodiments, the phase shift of the replication mode phase shift circuit 210 is applied by performing element-wise multiplication 312 on the sign matrix 311 containing columns 304 to 310 and the matrix stack 316. For example, matrix H may contain only matrices with a magnitude of 1 (e.g., 1, -1, e). jπ / 4 The numbers (etc.) are then passed through a multiplication process to shift the sign. After the shifted sign columns 320 to 326 are passed to the inverse FFT to convert them into time-domain signals.

[0101] In some embodiments, matrix H 314 may have more columns than the number of replicas (D), and / or the number of frequency modulations (e.g., subcarriers) of resource elements may not be divisible by the number of rows in matrix H 314. Matrix stack 316 may be larger than the symbol matrix, and matrix stack 316 may be truncated by removing regions 318 separated by dashed lines, as shown.

[0102] In some embodiments, the matrix stack may contain elements associated with pilot subcarriers, wherein the elements are not 1 (e.g., a phase shift is specified for the elements). The elements may be replaced with the number 1 so that no phase shift is applied to the pilot subcarriers.

[0103] In some embodiments, it is desirable that the first copy (e.g., the first resource unit) has no phase shift applied to any of its symbols. To eliminate the phase shift associated with the first resource unit while maintaining the desired PAPR reduction, the complex conjugate of the first column can be element-wise multiplied by each column of the matrix stack (including the first column).

[0104] In some embodiments, the subcarrier index (e.g., as part of the symbol matrix) may be permuted before multiplication by matrix stack 316. After multiplication, the permutation may be reversed (e.g., canceled, inverted) so that the symbols are in the proper positions before the inverse FFT is applied. In some embodiments, a linear transformation of matrix 314 may be performed before generating matrix stack 316. For example, the matrix may be multiplied by -1 (e.g., to change the received phase-shifted signal). Rows and / or columns of matrix 314 may also be permuted before generating matrix stack.

[0105] The size of matrix H, relative to the replication mode, can significantly affect the final PAPR reduction. Hadamard matrices (e.g., those with orthogonal rows) provide a significant reduction in PAPR. Three different matrices for matrix H 314 were investigated for a 52-frequency modulated resource unit (e.g., RU52-DUP4) that has been replicated four times. Standard Hadamard matrix of size 4:

[0106]

[0107] A cyclic Hadamard matrix of size 4:

[0108]

[0109] and a complex Hadamard matrix of size 4:

[0110]

[0111] like Figure 1D As shown by the dotted lines, both the cyclic Hadamard matrix of size 4 and the standard Hadamard matrix provide similar PAPR. For values ​​of α = 0 or π, the complex Hadamard matrix provides a median PAPR that is approximately 0.5 dB lower than the other Hadamard matrices, and for α = π / 2, the complex Hadamard matrix provides a median PAPR reduction of approximately 0.25 dB.

[0112] Further matrix tests were performed for different constellation diagrams (e.g., BPSK and QPSK). As indicated in Table 1 below, all matrix and replication modes were able to reduce the median PAPR to less than the median PAPR of the 242 FM resource unit baseline.

[0113]

[0114] Table 1: Empirical PAPR Results

[0115] RU242 indicates a 242-frequency modulation resource unit (FM Resource Unit) transmission. RU52 indicates a single (e.g., unreplicated) 52-FM Resource Unit transmission. 4xDUP RU52 indicates a 52-FM Resource Unit transmission replicated four times. 4xDUP RU52 P4 indicates a transmission replicated four times using a standard Hadamard matrix of size 4 following a reference. Figure 3A The described procedure undergoes a phase-shifted 52-frequency modulated resource unit transmission, with 8xDUP RU26 P8 indicating that it is copied 8 times using a standard Hadamard matrix of size 8, following the reference. Figure 3A The described procedure undergoes a 26-frequency modulation resource unit transmission with phase shift, 9xDUP RU26 P9 indicating that it is copied 9 times, using a multiphase matrix of size 9 following a reference. Figure 3A The described procedure, which involves transmission of 26 frequency modulation resource units with phase shift, is defined as follows:

[0116] Where x n =e jn2π / 9 ,

[0117] Furthermore, 9xDUP RU26 P32 indicates that the matrix was copied 9 times, using a standard Hadamard matrix of size 32, following the reference. Figure 3A The described procedure involves transmission of 26 frequency modulation resource units with phase shift.

[0118] It should be understood that although many of the examples in this document are described for 52-mod or 26-mod resource units with 4, 8, or 9 copies, the procedures described can be applied to communication strategies that use any number of mods and / or any number of copies within a resource unit.

[0119] refer to Figure 3B The operation of the replica mode phase shift circuit 260 of the receiver is illustrated according to some embodiments. For example, Figure 3B The phase shift is applied by performing element-wise matrix multiplication on the symbols received from FFT circuit 258. Replication mode phase shift circuit 260 can be configured to arrange symbols in a manner similar to that of the transmitter's replication mode phase shift circuit 210. For example, symbols associated with resource units can be ordered into single columns (e.g., columns 352, 354, 356, 358) and combined to form symbol matrix 359.

[0120] In some embodiments, a matrix H*362 is generated to cancel or reverse the phase shift applied within the transmitter. Matrix H*362 may be defined as the element-wise complex conjugate of matrix H314 from the replica-mode phase shift circuit 210 of the transmitter. Matrix H*362 may be arranged in a segmented columnar configuration (e.g., one matrix H*362 sits on top of the next matrix H*362, and so on) to form a matrix stack 364.

[0121] Element-wise matrix multiplication 360 can be performed to apply the phase shift of the receiver (e.g., to reverse the phase shift of the transmitter). Note that if the elements of matrix H 314 and matrix H*362 are complex conjugates, then after two multiplications, the symbols may no longer be phase-shifted and can be compared with a constellation diagram (e.g., in symbol mapping circuitry 262). As described in the reference transmitter, matrix H*364 may have more than D columns, and / or the number of frequency modulations (e.g., subcarriers) of resource elements may not be divisible by the number of rows in matrix H*364. Matrix stack 364 may be larger than the symbol matrix, and matrix stack 364 can be truncated by removing the region 366 separated by dashed lines, as shown.

[0122] After element-wise matrix multiplication 360, each resource unit should contain the same symbol in the corresponding column (e.g., columns 368 to 374). These symbols can be combined into a single column of symbols 376, which can be ordered into a useful data stream by data streaming circuitry 266. Long-distance travel attenuation, multipath interference, etc., can cause some symbols to be incorrectly recovered, and the replicated versions of the symbols can be used to determine the symbols most likely to be transmitted. Symbols can first be converted to their binary data symbol form using a constellation diagram. Each recovered bit can be subject to a majority-voting combination strategy. For example, in a transmission using QPSK replication four times, if the received symbols in each resource unit at a given index are '01', '01', '11', '01', then the majority-voting combination strategy will output '01' as the data symbol recovered from three of the four subcarriers. Combining can be performed on the entire data symbol (e.g., two bits in QPSK) or bit-by-bit. In some embodiments, the recovered symbols (e.g., magnitudes and phases) in each resource unit of a given index (e.g., rows of the replicated symbol matrix 361) are averaged by performing a vector average or other suitable technique before being converted into data symbols using a constellation diagram.

[0123] Operating procedures

[0124] The method described in this paper allows for the benefits of replicated mode OFDMA transmission (including redundancy and error recovery capabilities) while maintaining acceptable PAPR, thus allowing for similar signal transmission power as non-replicated mode transmission.

[0125] refer to Figure 4AOperation flow 400 illustrates operations for replica mode transmission using phase shift according to some embodiments. For example, flow 400 can be executed by circuitry of OFDMA transmission system 200. Flow 400 may include mapping a number of data symbols to magnitudes and phases in operation 402 to generate multiple symbols. For example, binary data symbols (e.g., individual bits or bit sequences) can be assigned to subcarriers (e.g., frequency modulation) of resource units and the binary data symbols can be converted into corresponding symbols using a constellation diagram for the desired communication technology (e.g., BPSK, QPSK, etc.).

[0126] In some embodiments, process 400 includes applying a first set of corresponding phase shifts to symbols in operation 404 to form a first set of shifted symbols. It is not necessary for all symbols to receive a phase shift. For example, a symbol assigned to every fourth subcarrier index may receive a 180° phase shift (e.g., multiplied by -1). Other phase shifts may also be applied, for example, by multiplying by e. jπ / 2 A 90° phase shift is applied. In some embodiments, process 400 includes applying a second set of corresponding phase shifts to symbols in operation 406 to form a second set of shifted symbols. When generating the second set of shifted symbols, phase shifts may be applied to different symbols. For example, every fourth subcarrier index may receive a 180° phase shift (e.g., multiplied by -1), but starting with the second subcarrier (e.g., the second frequency modulation or resource element) index instead of the first subcarrier index.

[0127] In some embodiments, the resulting sets of shifted symbols (e.g., generated in operations 404 and 406) are assigned to subcarriers of different resource units. The same data symbols are used to generate two sets of shifted symbols, so both resource units are transmitting the same data. Advantageously, due to the various phase shifts, the PAPR of the duplicated transmission does not increase excessively.

[0128] In some embodiments, process 400 includes generating a time-domain signal based on a first set of shifted symbols and a second set of shifted symbols in operation 408. The time-domain signal can be determined by performing an inverse Fourier transform (e.g., inverse FFT) on the subcarrier spectrum assigned with associated shifted symbols. A single time-domain signal may have a duration that depends on the subcarrier frequency interval. For example, the duration of the time-domain signal may be the reciprocal of the subcarrier frequency interval (e.g., 12.8 μs for a 78.125 kHz interval). In some embodiments, guard periods may be added to the beginning and / or end of the time-domain signal, and no useful data may be transmitted during these periods. When multipath propagation delay is a concern, guard periods can be used to prevent one time-domain signal from interfering with the next. Process 400 may include transmitting the time-domain signal in operation 410.

[0129] refer to Figure 4BOperation flow 420 illustrates operations according to some embodiments for applying phase shift to various symbols by performing matrix multiplication. For example, flow 420 may be performed by replication mode phase shift circuitry 210 and / or 260. Phase shift can be applied by multiplying a symbol by a number having a magnitude of 1 and the desired phase shift (e.g., a complex number). In some embodiments, flow 420 includes forming a symbol matrix (e.g., symbol matrix 311) in operation 422, the symbol matrix containing a first column and a second column containing symbols. Each column may represent a symbol that will ultimately be assigned to a resource unit. More than two columns may be used; for example, symbols may be replicated four, eight, nine, etc., based on the selected replication mode. As part of the replication process, each row of the symbol matrix may be an index of a subcarrier receiving the same symbol.

[0130] In some embodiments, process 420 includes generating a matrix stack (e.g., matrix stack 316) in operation 424, the matrix stack containing matrices arranged in a divided columnar form (e.g., matrix 314). For example, matrices may be repeated and organized such that there is a column of repeating matrices, one repeating matrix on top of another repeating matrix. Matrixes may have more columns than symbolic matrices and may be repeated a certain number of times, such that the matrix stack has more rows than symbolic matrices. Several suitable matrices have been previously described that produce reduced PAPR when used to apply phase shifts by the techniques described herein. For example, matrices may be Hadamard matrices of size 4, 8, or 32; cyclic Hadamard matrices; complex Hadamard matrices; polyphase matrices of size 9; or any other suitable matrices.

[0131] Process 420 may include truncating the matrix stack in operation 426 such that the matrix stack has the same number of rows and columns as the symbol matrix. For example, excessive columns and rows may be removed. In some embodiments, process 420 may include performing element-wise multiplication of the symbol matrix and the matrix stack in operation 428. After the multiplication, a phase shift has been appropriately applied to the symbols assigned to the individual resource units.

[0132] refer to Figure 5 Operation flow 500 illustrates operations for receiving OFDMA transmissions with phase shift in a replication mode, according to some embodiments. For example, flow 500 may be performed by OFDMA receiver system 250. In some embodiments, in operation 502, a time-domain signal representing a number of data symbols is received. Flow 500 may include extracting a first set of shifted symbols from a subcarrier of a first resource unit and a second set of shifted symbols from a subcarrier of a second resource unit. For example, FFT may be used to perform the process of extracting the shifted symbols from the subcarriers.

[0133] In some embodiments, process 500 includes applying a first set of corresponding phase shifts to a first set of shifted symbols in operation 506 to generate a first set of symbols. Process 500 may also include applying a second set of corresponding phase shifts to a second set of shifted symbols in operation 508 to generate a second set of symbols. The phase shifts applied in operations 506 and / or 508 can be reversed (e.g., canceled) the phase shifts applied during transmission. Phase shifts can be pre-arranged, for example, stored in the software or firmware of the transmitter and receiver. In some embodiments, the transmitter can determine the phase shifts to be used and send the necessary information (e.g., the phase shift or its inverse element) to the receiver, such that the shift can be revoked and the symbols can be recovered. In some embodiments, the phase shifts applied in operations 506 and 508 can be performed by performing operations as described in reference... Figure 3B The described element-wise matrix multiplications are performed in parallel using operations from process 420.

[0134] In some embodiments, process 500 includes combining a first group of symbols with a second group of symbols in operation 510 to form a third group of symbols. For example, the combination of symbols can be performed by vector averaging of the symbols corresponding to the subcarrier indices assigned to carry replicated data. For example, the subcarrier indices carrying replicated data may depend on the mode (e.g., replication mode). After the symbols have been combined in operation 510, the resulting symbols from the third group of symbols can be mapped to data symbols in operation 512 (e.g., using the magnitude and phase of the symbols). The data symbols can be converted into a stream to complete data reception.

[0135] In some embodiments, symbols are mapped to data symbols before being combined, and the combination is performed on a bit-by-bit basis. For example, bits generated by combining bits of multiple resource units can be obtained through majority voting.

[0136] Configuration of exemplary embodiments

[0137] As used herein, the terms “about,” “approximately,” “substantially,” and similar terms are intended to have a broad meaning consistent with common and accepted usage by those skilled in the art to which this disclosure pertains. Those skilled in the art who examine the subject matter of this disclosure will understand that these terms are intended to allow for the description of specific features described and claimed without limiting the scope of those features to the precise numerical ranges provided. Therefore, these terms should be interpreted as indicating that any non-substantial or unreasonable modification or alteration to the described and claimed subject matter is considered within the scope of this disclosure, as set forth in the appended claims.

[0138] It should be noted that the term "exemplary" and its variations used herein to describe various embodiments are intended to indicate that such embodiments are possible instances, representations or illustrations of possible embodiments (and such terms are not intended to imply that such embodiments are necessarily unusual or the highest level of instances).

[0139] The construction and arrangement of the systems and methods shown in the various exemplary embodiments are illustrative only. While only a few embodiments are described in detail in this disclosure, many modifications are possible (e.g., variations in the number of ports or destinations, data types, methods of re-insertion, reintroduction, parameter values, arrangements, etc.). For example, the positions of elements may be reversed or otherwise changed, connections between elements may be direct or indirect, such that one or more intermediate elements may connect elements, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps may be varied or reordered according to alternative embodiments. Other substitutions, modifications, alterations, and omissions may be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of this disclosure. For example, embodiments of this disclosure may be implemented by a single device and / or system or by a combination of single devices and / or systems.

[0140] As used herein, the term "or" is used in its inclusive sense (rather than its exclusive sense), and therefore, when used to connect lists of elements, the term "or" means one, some, or all of the elements in the list. Unless otherwise specifically stated, connectives such as the phrase "at least one of X, Y, and Z" are understood to mean that the elements may be X, Y, and Z; X and Y; X and Z; Y and Z; or X, Y, and Z (i.e., any combination of X, Y, and Z). Therefore, unless otherwise indicated, this connective is generally not intended to imply that a particular embodiment requires each of at least one of X, at least one of Y, and at least one of Z to be presented.

[0141] References to element positions (i.e., "top", "bottom", "above", "below") herein are used only to describe the orientation of the various elements in the figures. It should be noted that the orientation of the various elements may differ according to other exemplary embodiments, and such variations are intended to be encompassed by this disclosure.

[0142] While the figures illustrate a specific order of method steps, the order of these steps may differ from the depicted order. Furthermore, two or more steps may be performed simultaneously or partially simultaneously. This variation will depend on the chosen software and hardware and on the designer's choice. All such variations are within the scope of this disclosure. Similarly, software implementations can be implemented using standard programming techniques with rule-based logic and other logic to implement various connection steps, processing steps, comparison steps, and decision steps.

[0143] This disclosure covers methods, systems, and program products on any machine-readable medium for implementing various operations. Embodiments of this disclosure may be implemented using existing computer processors or dedicated computer processors incorporated by suitable systems for this or another purpose, or via hard-wired systems. Embodiments within the scope of this disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. This machine-readable medium may be any available medium accessible by a general-purpose or special-purpose computer or other machine having a processor. By way of example, this machine-readable medium may include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and accessible by a general-purpose or special-purpose computer (i.e., ASIC or FPGA) or other machine having a processor. Combinations of the above are also included within the scope of computer-readable media. For example, machine-executable instructions comprise instructions and data that cause a general-purpose computer, special-purpose computer, or special-purpose processing machine to perform a particular function or group of functions.

Claims

1. A system comprising: One or more circuits configured to perform operations including the following: Map multiple data symbols to magnitudes and phases to generate multiple symbols; The first set of corresponding phase shifts is applied to the plurality of symbols to generate a first plurality of shifted symbols; The second set of corresponding phase shifts is applied to the plurality of symbols to generate a second plurality of shifted symbols; A time-domain signal is generated based on the first plurality of shift symbols and the second plurality of shift symbols; and Transmit the time-domain signal, The first plurality of shifted symbols are assigned to the first plurality of subcarriers from the first resource unit, and the second plurality of shifted symbols are assigned to the second plurality of subcarriers from the second resource unit.

2. The system according to claim 1, wherein the operation further comprises: A symbol matrix is ​​formed, the symbol matrix including a first column containing the plurality of symbols and a second column containing the plurality of symbols; and Generate a matrix stack, the matrix stack comprising matrices arranged in a partitioned columnar format. The number of columns in the symbol matrix is ​​equal to the number of resource units used for transmitting the duplicate symbol transmissions of the plurality of symbols. The elements of the symbol matrix include corresponding symbols from the plurality of symbols, and the elements are defined by columns associated with resource elements and rows associated with subcarriers of the resource elements. The first set of corresponding phase shifts and the second set of corresponding phase shifts are applied by performing element-wise multiplication of the symbol matrix and the matrix stack.

3. The system according to claim 2, wherein the elements of the matrix have a value of 1.

4. The system according to claim 3, wherein the rows of the matrix are orthogonal vectors.

5. The system according to claim 4, wherein the matrix is ​​a cyclic Hadamard matrix.

6. The system of claim 2, wherein the element in the matrix stack multiplied by the corresponding element in the symbol matrix corresponding to the pilot subcarrier is set to 1.

7. The system of claim 2, wherein the complex conjugate of the first column of the matrix stack is used to perform the element-wise multiplication on each column of the matrix stack.

8. The system according to claim 2, wherein: The number of subcarriers in each of the resource units represented by the corresponding elements of the symbol matrix cannot be divided by the number of rows in the matrix. The matrix is ​​repeated to form the matrix stack, the matrix stack having a greater number of stack rows than the number of subcarriers in each of the resource elements, and A certain number of the last rows of the matrix stack are removed from the matrix stack.

9. The system according to claim 2, wherein: The matrix has more columns than the number of columns in the symbol matrix, and A certain number of the last columns of the matrix stack are removed from the matrix stack.

10. The system of claim 1, wherein phase shift is not applied to symbols assigned to pilot subcarriers.

11. The system according to claim 1, wherein: There are 52 subcarriers in the first resource unit and 52 subcarriers in the second resource unit, and the plurality of symbols are copied across four resource units, or There are 26 subcarriers in the first resource unit and 26 subcarriers in the second resource unit, and the plurality of symbols are copied across eight resource units.

12. A method comprising: Mapping multiple data symbols to magnitudes and phases to generate multiple symbols; The first set of corresponding phase shifts is applied to the plurality of symbols to generate a first plurality of shifted symbols; The second set of corresponding phase shifts is applied to the plurality of symbols to generate a second plurality of shifted symbols; A time-domain signal is generated based on the first plurality of shift symbols and the second plurality of shift symbols; and Transmit the time-domain signal, The first plurality of shifted symbols are assigned to the first plurality of subcarriers from the first resource unit, and the second plurality of shifted symbols are assigned to the second plurality of subcarriers from the second resource unit.

13. The method of claim 12, further comprising: A symbol matrix is ​​formed, the symbol matrix including a first column containing the plurality of symbols and a second column containing the plurality of symbols; and Generate a matrix stack, the matrix stack comprising matrices arranged in a partitioned columnar format. The number of columns in the symbol matrix is ​​equal to the number of resource units used for transmitting the duplicate symbol transmissions of the plurality of symbols. The elements of the symbol matrix include corresponding symbols from the plurality of symbols, and the elements are defined by columns associated with resource elements and rows associated with subcarriers of the resource elements. The first set of corresponding phase shifts and the second set of corresponding phase shifts are applied by performing element-wise multiplication of the symbol matrix and the matrix stack.

14. The method of claim 13, wherein the elements of the matrix have a value of 1.

15. The method of claim 14, wherein the matrix is ​​a cyclic Hadamard matrix.

16. The method of claim 13, wherein the element in the matrix stack multiplied by the corresponding element in the symbol matrix corresponding to the pilot subcarrier is set to 1.

17. The method of claim 13, wherein the complex conjugate of the first column of the matrix stack is used to perform the element-wise multiplication on each column of the matrix stack.

18. An apparatus comprising: One or more circuits configured to perform operations including the following: Receive time-domain signals representing multiple data symbols; Extract a first plurality of shifted symbols from the subcarrier of the first resource unit and extract a second plurality of shifted symbols from the subcarrier of the second resource unit; The first set of corresponding phase shifts is applied to the first plurality of shifted symbols to generate the first plurality of symbols; The second set of corresponding phase shifts is applied to the second plurality of shifted symbols to generate the second plurality of symbols; The first plurality of symbols are combined with the second plurality of symbols to form a third plurality of symbols, wherein each of the third plurality of symbols is based at least on a first corresponding symbol among the first plurality of symbols and a second corresponding symbol among the second plurality of symbols; and The magnitude and phase of each of the third plurality of symbols are mapped to generate the plurality of data symbols.

19. The apparatus of claim 18, wherein the operation further comprises: A symbol matrix is ​​formed, the symbol matrix including a first column containing the first plurality of shifted symbols and a second column containing the second plurality of shifted symbols; and Generate a matrix stack, the matrix stack comprising matrices arranged in a partitioned columnar format. The number of columns in the symbol matrix is ​​equal to the number of resource units used to send the copied symbol transmission. The elements of the symbol matrix include corresponding shifted symbols from the first plurality of shifted symbols or the second plurality of shifted symbols, and the elements are defined by columns associated with resource elements and rows associated with subcarriers of the resource elements. The first set of corresponding phase shifts and the second set of corresponding phase shifts are applied by performing element-wise multiplication of the symbol matrix and the matrix stack.

20. The apparatus of claim 19, wherein the matrix is ​​an orthogonal matrix.

21. The apparatus of claim 19, wherein the matrix is ​​a cyclic Hadamard matrix.

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