DE102015101708B4 - Estimation of an uplink multi-user carrier frequency offset (CFO) in wireless communications - Google Patents

Abstract

A wireless communication device, comprising: a communication interface; anda processor, wherein the processor and communication interface are configured to: receive a first orthogonal frequency division multiple access (OFDMA) symbol, the first data from a first other wireless communication device modulated on a first at least one subcarrier, and second data from a second other wireless communication device modulated on a second at least one subcarrier comprises: receiving a second OFDMA symbol representing a copy of the first data from the first other wireless communication device modulated on the first at least one subcarrier, and a copy of the second data from the second other wireless communication device modulated on the second at least one sub-carrier comprises processing the first data and the copy of the first data to determine a first carrier frequency coincident with the first other wireless communication device the second data and the copy of the second data to determine a second carrier frequency associated with the second other wireless communication device; determining a first carrier frequency offset (CFO) associated with the first other wireless communication device based on the first carrier frequency and a frequency reference associated with the wireless communication device; determining a second CFO associated with the second other wireless communication device based on the second carrier frequency and the frequency reference associated with the wireless communication device linked; receive the first OFDMA symbol, which also comprises third data from the first other wireless communication device modulated on a third at least one subcarrier and fourth data from the second other wireless communication device modulated on a fourth at least one subcarrier a third OFDMA symbol receiving a copy of the third data from the first other wireless communication device modulated on the third at least one subcarrier and a copy of the fourth data from the second other wireless communication device residing on the fourth at least one a subcarrier is modulated, wherein the second OFDMA symbol and the third OFDMA symbol are separated by at least one other OFDMA symbol to process the first data, the copy of the first data, the third data, and the copy of the third data to determine the first carrier frequency associated with the first and second carrier frequencies he wireless communication device is linked; and process the second data, the copy of the second data, the fourth data and the copy of the fourth data to determine the second carrier frequency associated with the second other wireless communication device.

Description

BACKGROUND

TECHNICAL AREA

The present disclosure relates generally to communication systems; and more particularly frequency and frequency offset estimation in single user, multi-user, multiple-access and / or MIMO wireless communications.

DESCRIPTION OF THE PRIOR ART

Communication systems support wireless and wired communications between wireless and / or wired communication devices. The systems may range from national and / or international mobile telephone systems to the Internet and wireless point-to-point home networks, and may operate in accordance with one or more communication standards. For example, wireless communication systems according to one or more standards may include, but are not limited to, IEEE 802.11x (where x may be one of many extensions, such as a, b, n, g, etc.), Bluetooth, "Advanced Mobile Phone Services "(AMPS), Digital AMPS, Global System for Mobile Communications (GSM), etc., and / or variations of these work.

In some cases, wireless communication is performed between a transmitter (TX) and a receiver (RX) using single-input-single-output (SISO) communication. Another type of wireless communication is single-input-multiple-output (SIMO), where a single TX processes data into radio frequency (RF) signals that are transmitted to an RX that is two or more Antennas and two or more RX paths includes.

An alternative type of wireless communication is a multiple-input-single-ouptut (MISO) where a TX comprises two or more transmission paths, each corresponding to converting a corresponding portion of a baseband signal to RF signals be transmitted via antennas to an RX. Another type of wireless communication is a multiple-input-multiple-output (MIMO), where a TX and RX respectively comprise a plurality of paths, such that a TX carries data in parallel using a spatial and temporal coding function is processed to produce two or more data streams, and an RX receives the plurality of RF signals over multiple RX paths that recover the data streams using a spatial and temporal decoding function.

In the various types of wireless communication systems, synchronization is often performed between the various wireless communication devices to ensure correct communication.

For example, various signals may be communicated between the devices to ensure that a given device has accurate information regarding the operational characteristics of one or more of the other devices. There are several ways in which such information is communicated between devices, where there is still room for improvement in the manner in which such information is determined and communicated between devices to improve overall performance of the communication system.

US 2010/0080112 A1 describes a wireless transmission method which estimates in a base station an offset of the carrier frequency of a received OFDM transmission from a terminal accessing an OFDMA radio access network.

US 2006/0233270 A1 describes a method for uplink carrier frequency synchronization in an OFDMA system wherein an offset of a carrier frequency is estimated using training symbols in the frequency domain and compensated during a training symbol transmission interval.

WO 2011/008776 A1 describes a method for wireless communication that generates a LTF (long training field) sequence by combining a plurality of interpolated sequences and at least one other sequence that is repeated multiple times to peak-to-average power ratio (PAPR) during a transmission to reduce the generated LTF sequence.

It is an object of the present invention to provide a wireless communication device and method that improves the overall performance of a communication system.

This object is achieved by a wireless communication device having the features of claim 1 and claim 8 and by a method having the features of claim 13.

Advantageous developments emerge from the dependent subclaims.

list of figures

• 1 Fig. 10 is a diagram illustrating an embodiment of a wireless communication system.
• 2 FIG. 13 is a diagram illustrating one embodiment of a dense distribution of wireless communication devices. FIG.
• 3A Fig. 10 is a diagram illustrating an example of communication between wireless communication devices.
• 3B Fig. 10 is a diagram illustrating another example of communication between wireless communication devices.
• 3C Fig. 10 is a diagram illustrating another example of communication between wireless communication devices.
• 4A Fig. 12 is a diagram illustrating an example of Orthogonal Frequency Division Multiplexing (OFDM) and / or Orthogonal Frequency Division Multiple Access (OFDMA).
• 4B FIG. 13 is a diagram illustrating another example of OFDM and / or OFDMA.
• 4C FIG. 13 is a diagram illustrating another example of OFDM and / or OFDMA.
• 4D FIG. 13 is a diagram illustrating another example of OFDM and / or OFDMA.
• 5A FIG. 13 is a diagram illustrating an example of OFDMA symbols other than wireless ones Communication devices for use by a wireless communication device are received to perform a carrier frequency offset estimation (CFO estimate).
• 5B FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 5C FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 5D FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 5E FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 5F FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 6A FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 6B FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 6C FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 6D FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 7A FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 7B FIG. 12 is a diagram illustrating another example of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 8A FIG. 12 is a diagram illustrating an example of OFDMA symbols comprising long training fields (LTFs) received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 8B FIG. 12 is a diagram illustrating another example of OFDMA symbols comprising LTFs received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 8C FIG. 12 is a diagram illustrating another example of OFDMA symbols comprising LTFs received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 9A FIG. 12 is a diagram illustrating another example of OFDMA symbols comprising LTFs received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation.
• 9B Fig. 10 is a diagram illustrating an example of processing data included in an OFDMA symbol device to perform a CFO estimation.
• 9C Fig. 12 is a diagram illustrating another example of processing data included in an OFDMA symbol device to perform a CFO estimation.
• 10A FIG. 10 is a diagram illustrating one embodiment of a method for execution by one or more wireless communication devices. FIG.
• 10B FIG. 12 is a diagram illustrating another embodiment of a method for execution by one or more wireless communication devices.

DETAILED DESCRIPTION

1 is a diagram illustrating an embodiment of a wireless communication system 100 represents. The wireless communication system 100 includes base stations and / or access points 112 to 116 , wireless communication devices 118 to 132 (for example, wireless stations (STAs)) and a network hardware component 134 , The wireless communication devices 118 to 132 can laptop computers, tablets 118 and 126 , Personal Digital Assistants 120 and 132 , Personal Computers 124 and 132 and / or mobile phones 122 and 128 be. The details of one embodiment of such wireless communication devices will be explained in more detail with reference to FIG 3A described.

The Base Stations (BSs) or Access Points (APs) 112 to 116 are via local area network connections or LAN connection 136 . 138 and 140 with the network hardware 134 operatively linked. The network hardware 134 , which may be a router, a switch, a bridge, a modem, a system controller, etc., provides a wide area network (WAN) connection 142 for the communication system 100 ready. Each of the base stations or each of the access points 112 to 116 has an associated antenna or antenna array to communicate with the wireless communication devices in its area. Typically, the wireless communication devices register with a particular base station or access point 112 to 116 to services from the communication system 100 to recieve. For direct connections (that is, point-to-point communications), wireless communication devices communicate directly over an assigned channel.

The many wireless communication devices (WDEVs) 118 to 132 and BSs or APs 112 to 116 may include a processor and a communication interface for communicating with any other of the wireless communication devices 118 to 132 and BSs or APs 112 to support 116. In an example of an operation, a processor and the communication interface included in one of the devices (eg, any of the WDEVs 118 to 132 and BSs or APs 112 to 116 ) are configured to process at least one signal received from another of the devices and / or to generate at least one signal to be transmitted to another of the devices (e.g., any other of the WDEVs 118 to 132 and BSs or APs 112 to 116 ).

It should be noted that a general reference to a communication device, such as a wireless communication device (eg, WDEVs) 118 to 132 and BSs or APs 112 to 116 in 1 or any other communication devices and / or wireless communication devices, alternatively, may generally be made using the term "device" (for example, with reference to FIGS 2 "Device 210" when referring to "wireless communication device 210" or "WDEV 210" or "devices 210 to 234" when referring to "wireless communication devices 210 to 234 "; or with reference to 3 For example, the use of "device 310" when referring to "wireless communication device 310" or "devices 390 and 391 (or 390 to 391)" may alternatively be used when referring to wireless communication devices 390 and 391 or WDEVs 390 and 391 Is referred).

The processor and communication interface of any of the many facilities WDEVs 118 to 132 and BSs or APs 112 to 116 may be configured to communicate with other of the many WDEVs facilities 118 to 132 and BSs or APs 112 to 116 to support. Such communications between devices may be unidirectional or bidirectional. Likewise, such communications between devices may be unidirectional at one time and bidirectional at another time.

In one example of an operation, the facility includes 116 (for example, a BS or an AP) a communication interface and a processor that are configured to receive one or more of the signals (eg Orthogonal Frequency Division Multiple Access (OFDMA) symbols). 181 ) of facility 130 and 132 to recieve. Considering an OFDMA example, facility uses 130 a first at least one subcarrier and used device 132 a second at least one subcarrier. Generally, different subsets of subcarriers are assigned for use by different devices. Such an assignment may be dynamic, adaptive, etc. for different devices for different symbols and / or at different times. The device 116 receives a first OFDMA symbol comprising first data from a device 130 which are modulated on a first at least one subcarrier, and second data from a device 132 which are modulated on a second at least one subcarrier. Then the device receives 116 a second OFDM symbol representing a copy or repetition of the first data from the device 130 which are modulated on the first at least one sub-carrier, and a copy or a repetition of the second data from the device 132 comprises, which are modulated on a second at least one subcarrier. The device 116 processes the first data and the copy or repetition of the first data to determine a first carrier frequency associated with the device 130 is linked. The device 116 also processes the second data and the copy or repetition of the second data to determine a second carrier frequency associated with the device 132 is linked. The device 116 then determines a first carrier frequency offset (CFO) associated with the device 130 linked, and a second CFO who is equipped with 132 based on the first and second carrier frequencies, respectively, and a frequency reference of the device 116 , Such a capability within the facility 116 may generally be referred to as a CFO determinability 116a. With respect to this embodiment and other embodiments or examples provided herein, it should be noted that there may be cases where the particular CFO associated with another device is zero so there is no CFO between the device 116 and this other device gives.

Generally, the device works 116 by processing data and at least one copy or repetition of that data from another device contained within the same at least one subcarrier. A number of different combinations of such data and copies and / or repetitions of this data may be used in various embodiments. If the device 116 The CFO, who is linked to another device with which it communicates, can use the facility 116 Modify or adapt communications to and / or from this device to compensate for any CFO that exists between the device 116 and other means to ensure effective communications, synchronization and improved performance of the communications between the devices.

2 FIG. 12 is a diagram illustrating one embodiment 200 of a dense distribution of wireless communication devices (shown in the diagram as WDEVs). Any of the many WDEVs 210 to 234 may be access points (APs) or wireless stations (STAs). For example, WDEV 210 an AP or an AP-operated or AP working STA, which with WDEVs 212 , 214, 216 and 218, which are STAs, communicates. WDEV 220 may be an AP or an AP-powered STA that uses WDEVs 222 . 224 . 226 and 228 who are STAs communicate. In certain cases, at least one additional AP or AP-powered STA may be employed, such as WDEV 230 that with WDEVs 232 and 234 communicates that are STAs. The STAs may be any type of one or more types of wireless communication devices, including wireless communication devices 118 to 132 and the APs or AP-powered STAs may be any type of one or more wireless communication devices, including a BSs or an AP 212 to 216 be. Different groups of WDEVs 210 to 234 can be divided into different basic service sets (BSSs). In some cases, at least one of the WDEVs 210 to 234 within at least one overlapping basic services set (OBSS) covering two or more BSSs. As described above with linking WDEVs in an AP-STA relationship, one of the WDEVs may be operational as an AP and certain of the WDEVs may be implemented within the same Basic Service Set (BSS).

This disclosure presents new architectures, methods, approaches, etc. which have been improved Enable spatial reuse for WiFi or next-generation wireless local area network (WLAN) systems. It is expected that next-generation WiFi systems will provide a dense distribution performance in which many clients and APs may be within a given range (which may be, for example, an indoor and / or outdoor area with a high density of facilities, such as a train station, airport, stadium, building, mall, arenas, convention centers, colleges, city centers, etc., to name but a few examples). A large number of devices operating within a given range may be problematic, if not impossible, using prior technologies.

In an example of an operation, WDEV includes 210 a communication interface and a processor configured to provide Orthogonal Frequency Division Multiple Access (OFDMA) symbols 281 from WDEVs 212 and 214 to recieve. WDEV 212 uses a first at least one subcarrier and WDEV 214 uses a second at least one subcarrier. Generally, different subsets of subcarriers are assigned for use by different devices. The WDEV 210 receives a first OFDMA symbol containing first data from WDEV 212 which are modulated on a first at least one subcarrier and second data of WDEV 214 modulated on a second at least one subcarrier. Then WDEV receives 210 a second OFDM symbol that copies or repeats the first data from WDEV 212 which are modulated on a first at least one sub-carrier, and a copy or repetition of the second data of WDEV 214 which are modulated on a second at least one subcarrier comprises. The WDEV 210 Processes the first data and the copy or repetition of the first data to determine a first carrier frequency associated with WDEV 212 is linked. The WDEV 210 also processes the second data and the copy or repetition of the second data to determine a second carrier frequency associated with WDEV 214 is linked. The WDEV 210 then determines a first carrier frequency offset (CFO) that corresponds to WDEV 212 is linked, and a second CFO, with WDEV 214 based on respective first and second carrier frequencies and a frequency reference of WDEV 210 , Such an ability within the WDEV 210 can be considered as a CFO determinability 210a be designated.

It should be noted that the determination of any CFOs between the WDEV 210 and other WDEVs may be performed multiple times with respect to several corresponding other WDEVs. For example, the WDEV 210 any CFOs with the WDEVs 216 and 218 at or during any other time. The WDEV 210 can any CFOs with the WDEVs 212 . 214 . 216 and 218 at or for any other time. It should also be noted that the WDEV 210 the CFO with the WDEVs 212 and 214 repeatedly at different times, if desired. In general, the determination of any CFOs by the WDEV 210 several times and with any desired group or combination of other WDEVs. It should also be noted that while many examples and embodiments provided herein describe the determination of any CFOs with respect to one or more other WDEVs, similar processing operations with respect to a single other device (e.g., such that WDEV 210 can work to the CFO only, if at all, from WDEV 212 can be performed at or during a given time).

3A FIG. 13 is a diagram illustrating an example 301 of communication between wireless communication devices. A wireless communication device 310 (which, for example, one of the facilities 118 to 132 regarding 1 may be) in communication with another wireless communication device via a transmission medium 390 , The wireless communication device 310 includes a communication interface 320 to perform transmitting and receiving at least one packet or frame (for example, using a transmitter 322 and a recipient 324 ) (note that a generic reference to a package or frame may be used interchangeably). Generally speaking, the communication interface 320 implemented to perform any operations of an analog front-end (AFE) and / or a physical layer (PHY) transmitter, receiver and / or transceiver. Examples of such operations may include any one or more of various operations including conversions between the frequency and / or analog or continuous time domains (such as the operations performed by a digital-to-analog converter (DAC) and / or an analog-to-digital converter). Converters (ADC), gain adaptation including scaling, filtering (for example, in either the digital or analog domain), frequency conversion (such as frequency upscaling or frequency scaling, such as baseband frequency, one or more the components of the device 310 are working), adjustment, pre-adjustment, Metric generation, symbol mapping and / or "de-mapping", automatic gain control (AGC), and / or any other operations performed by an AFE and / or a PHY component within a wireless communication device can be performed.

The wireless communication device 310 also includes a processor 330 and associated memory 340 configured to perform a plurality of operations, including interpreting at least one signal, symbol, packet, and / or frame, to a wireless communication device 390 is transmitted and / or from the wireless communication device 390 and / or the wireless communication device 391 Will be received. The wireless communication devices 310 and 390 (and / or 391) may be implemented using at least one integrated circuit according to any desired configuration or combination of components, modules, etc. within at least one integrated circuit. Similarly, the wireless communication devices 310, 390, and 391 may each include one or more antennas for transmitting and / or receiving at least one packet or frame (eg, the WDEV 390 m antennas and may include the WDEV 391 n antennas).

In an example of an operation, the communication interface 320 and the processor 330 the device 310 configured to perform certain operations, including sending and receiving communications with facilities 390 and 391 and processing and generation of such communications for facilities 390 and 391 are intended and received by these perform. In this example of an operation is the facility 310 configured to receive a first Orthogonal Frequency Division Multiple Access (OFDMA) symbol, the first data of the device 390 which are modulated on a first at least one sub-carrier and second data of device 391 which are modulated on a second at least one subcarrier comprises. The device 310 is also configured to receive a second OFDMA symbol which is a copy of the first data from the device 390 which are modulated on the first at least one sub-carrier, and a copy of the second data from the device 391 which are modulated on the second at least one subcarrier comprises. The device 310 is also configured to process the first data and the copy of the first data to determine a first carrier frequency associated with the device 390 and process the second data and the copy of the second data to determine a second carrier frequency associated with the device 391 is linked. Once this first and second carrier frequency, with the facilities 390 and 391 are known, is the device 310 also configured to provide a first carrier frequency offset (CFO) associated with the device 390 based on the first carrier frequency and a frequency reference associated with the device 310 is linked to determine, and a second CFO, with the facility 391 based on the second carrier frequency and the frequency reference associated with the device 310 linked to determine. The frequency reference associated with the device 310 may be a current operating frequency, a baseband frequency, a reference clock frequency, a predetermined or known frequency, and / or any other frequency reference associated with the device 310.

It should also be noted that the device 310 configured to determine the first and second carrier frequencies using any number of devices. For example, the device may 310 comprise a filter for determining whether or not the carrier frequency of the data and the copy of the data modulated on one or more subcarriers have a certain value. In the case that the data and the copy of the data have two different values, an average, a geometric Means or weighted average etc. of the two different values are used to estimate the actual carrier frequency associated with the device that has transmitted this data and the copy of that data. The device 310 may include multiple components, such as one or more of a frequency locked loop (FFL), a phase locked loop (PLL), a filter (eg, fixed, adjustable, selective, adaptive, etc., and any desired type, such as bandpass, bandstop, lowpass, notch, Butterworth filters, etc.), spectrum analyzer circuitry, spectrum analysis capability, etc., and / or any other means for use to determine a carrier frequency Data and the copy of the data modulated on one or more subcarriers. Regardless of the particular manner in which the carrier frequency of the data and the copy of the data is determined once the carrier frequency is known, the device compares 310 this carrier frequency with the frequency reference associated with the device 310 linked to any CFO of this data and the copy of the data associated with the device 390 or 391 linked to determine. In general, the carrier frequency of the data and the copy of the data may be considered as the center frequency, which is the average, geometric mean or weighted average, etc., between corresponding upper and lower cutoff frequencies.

It should be appreciated that the assignment of subcarriers to the devices 390 and 391 may be implemented in a number of different ways. For example, the assignment of subcarriers may be for use by the facilities 390 and 391 "A priori" or be known in advance during a linkage, such as that provided by the device 310, or based on communication and coordination between the devices 310 . 390 and or 391 be determined, etc. Regardless of the way in which the allocation of sub-carriers for the facilities 390 and 391 is made, data and copies or repetitions of these data in two or more OFDMA symbols, by the facilities 390 and 391 to the institution 310 be transferred for use by the device 310 to any CFOs with the facilities 390 and 391 linked relative to the device 310 to determine. Generally, the assignment of subcarriers for the facilities 390 and 391 made before the device 310 which receives two or more OFDMA symbols from the devices 390 and 391 for use to determine any CFOs associated with these devices.

It should also be noted that the data modulated within the one or more sub-carriers is one of the devices 390 or 391 may be of any desired shape or type. The data may be predetermined or defined, "a priori" or known beforehand, by one or more of the devices 310 . 390 and or 391 As long as the data is known to both the transmitting device (for example 390) and the receiving device (for example 310) and as long as the one or more subcarriers to which that data is modulated are within the appropriate two or more OFDMA symbols, then the receiving device (eg, 310) may process this data to determine any CFO that exists between the transmitting device (e.g., 390) and the receiving device (e.g., 310). It should also be noted that the reverse operation can be performed so that means 390 Communications of facility 310 can receive and determine whether any CFO exists between these devices.

3B FIG. 12 is a diagram illustrating another example 302 of communication between wireless communication devices. In this example 302 is the device 310 configured to use OFDMA symbols with other facilities including facility 390 , Facility 391 and optionally even more facilities up to facility 392 to transmit and receive. The device 310 receives two or more OFDMA symbols (shown, for example, as the first OFDMA symbol and the second OFDMA symbol) generated by devices 390 to 391 (or facilities 390 - 392 ) be transmitted. In some examples, the device represents 310 a sub-carrier assignment frame for the devices 390 - 391 (or facilities 390 - 392 ) before these facilities provide the OFDM symbols to the facility 310 transfer. Means 310 processes first data and a copy or repetition of the first data from the device 390 which are modulated on a first at least one sub-carrier, and second data and a copy or repetition of the second data of device 391 which are modulated on a second at least one sub-carrier to any of the CFOs of the devices 390 - 391 relative to device 310. Once any CFO of these facilities is known, the facility may 310 Communications required for facilities 390 - 391 are thought of or received from, based on any CFO associated with these devices, to modify or adapt to ensure effective communication and improve performance of communications between the devices. Considering an example in which device 310 is an access point (AP) and the devices 390-392 are wireless stations (STAs) may then have a downlink / downlink direction of device 310 as to the facilities 390 - 392 can be viewed, and can be uplink / uplink as from the facilities 390 -392 to the facility 310 to be viewed as.

3C FIG. 13 is a diagram illustrating another example 303 of communication between wireless communication devices. In this example 303 is the device 310 configured to use OFDMA symbols with other facilities including facility 390 . 391 . 392 , and 393 to transmit and receive. Generally speaking, the facility 310 be configured to communicate with one or more other devices up to N devices (where N is, for example, any positive integer greater than or equal to 1). In this diagram, the device receives 310 a first OFDMA symbol followed by a second OFDMA symbol of devices 390 to 393. The device 310 then receives a third OFDMA symbol such that one or more intervening symbols are included between the second OFDMA symbol and the third OFDMA symbol. It should be noted that this one or more intermediate symbols data and copies or Repetitions of the data with any of the facilities 390 - 393 for use in determining any CFO associated with these devices relative to device 310 , contain or may not contain. For example, this one or more intervening symbols may contain information other than those used to determine any CFO associated with those devices relative to the device 310 is linked include. Considering an example in which a facility 310 an AP is and the facilities 390 - 393 STAs are, then, can have a downlink / downlink direction than setup 310 to the facilities 390 - 393 can be viewed, and can be uplink / uplink as from the facilities 390 - 393 to the device 310.

4A FIG. 12 is a diagram illustrating an example 401 of Orthogonal Frequency Division Multiplexing (OFDM) and / or Orthogonal Frequency Division Multiple Access (OFDMA). A modulation of OFDM may be considered as splitting an available spectrum into a plurality of narrow band subcarriers (e.g., relatively low data rate carriers). The subcarriers are contained within an available frequency spectrum section or band. This available frequency spectrum is divided into the subcarriers or tones ("tones") used for the OFDM or OFDMA symbols and packets / frames. Usually, the frequency responses of these subcarriers are non-overlapping and orthogonal. Each subcarrier may be modulated using any of a variety of modulation coding techniques (as shown, for example, by the vertical axis of modulated data).

A communication device may be configured to perform an encoding of one or more bits to generate one or more coded bits that are used to generate the modulation data (or, more generally, data). For example, a processor and communication interface of a communication device may be configured to perform a forward error correction (FEC) or an error correction code (ECC) of one or more bits to encode one or more To generate bits. Examples of FEC and / or ECC may include a turbo code, a convolutional code, a "turbo trellis coded mudulation" (TTCM), a low density parity check code (LDPC) Reed-Solomon (RS) code, BCH (Bose and Ray-Chaudhuri and Hocquenghem) code, etc. The one or more coded bits may then be subjected to modulation or symbol mapping to generate modulation symbols. The modulation symbols may include data intended for one or more receiving devices. It should be noted that such modulation symbols can be generated using any of many types of modulation coding techniques. Examples of such modulation coding techniques may include binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), phase shift keying (PSK), 16 quadrature amplitude modulation (QAM), 32 amplitude and phase shift keying (APSK), etc., unencoded modulation, and / or any other desired type of modulation included Higher order modulations, which may include an even larger number of constellation points (eg, 1024 QAM, etc.).

4B FIG. 13 is a diagram illustrating another example 402 of OFDM and / or OFDMA. A transmitting device transmits modulation symbols via the subcarriers. OFDM and / or OFDMA modulation may operate by performing simultaneous transmission of a large number of narrow band (or multi-tone) carriers. In some applications, sometimes a guard interval (GI) or guard space is used between the many OFDM symbols to try to minimize the effects of ISI (intersymbol interference) caused by the effects of a multipath within the communication system which can be a concern especially in wireless communication systems. In addition, within the guard interval, a cyclic prefix (CP, "cyclic suffix") and / or a cyclic suffix (CS) (on the right of 4A shown), which may be a copy of the CP, may also be used to allow a switchover time (for example, to jump to a new communication channel or subchannel), and to help maintain orthogonality of the OFDM and / or OFDMA. Maintain symbols. Generally speaking, an OFDM and / or OFDMA system design is based on the expected delay spread within the communication system (e.g., the expected propagation delay of the communication channel).

In a single user system in which one or more OFDM symbols or OFDM packets / frames are transmitted between a transmitter device and a receiver device, all of the subcarriers or tones are for use in transmitting modulated data between the two Dedicated transmitter and receiver devices. In a multi-user system in which one or more OFDM symbols or OFDM packets / frames are transmitted between a transmitter device and a plurality of receivers or receivers, the plurality of subcarriers or tones may be mapped to correspondingly different receiver devices as described below with reference to FIG 4C is described.

4C FIG. 15 is a diagram illustrating another example 403 of OFDM and / or OFDMA. In comparison between OFDMA and OFDM, OFDMA is a multi-user version of the popular Orthogonal Frequency Division Multiplexing (OFDM) digital modulation scheme. Multiple access is achieved in OFDMA by assigning a subset of subcarriers to individual receivers or users. For example, first subcarriers / tones may be given to a user 1 second subcarriers / tones are assigned to a user 2 and so on, until any desired number of users are reached. In addition, such a subcarrier / tone assignment may be dynamic among different respective transmissions (eg, a first assignment for a first packet / frame, a second assignment for a second packet / frame, etc.). An OFDM packet / frame may include more than one OFDM symbol. Similarly, an OFDMA packet / frame may contain more than one OFDMA symbol. In addition, subcarrier / tone assignment among various corresponding symbols within a given packet / frame or superframe may be dynamic (e.g., a first assignment for a first OFDMA symbol within a packet / frame, a second assignment for a second OFDMA symbol within the package / frame, etc.). Generally speaking, an OFDMA symbol is a special kind of OFDM symbol and a general reference to an OFDM symbol herein includes both OFDM and OFDMA symbols (and a general reference to OFDM packets / frames herein includes both OFDM and OFDM symbols). as well as OFDMA packets / frames and vice versa). 4C Fig. 40 shows example 403 in which assignments of subcarriers to different users are intermixed (e.g., subcarriers assigned to a first user include non-adjacent subcarriers, and at least one subcarrier assigned to a second user is located between two subcarriers assigned to the first user). The different groups of subcarriers associated with each user may be considered as corresponding channels of a plurality of channels, all of which form the available subcarriers for OFDM signaling.

4D FIG. 13 is a diagram illustrating another example 404 of OFDM and / or OFDMA. In this example 404, the allocations of subcarriers to different users in different groups of neighboring subcarriers (for example, first subcarriers assigned to a first user include a first adjacent subcarrier group, second subcarriers assigned to a second user include one second adjacent subcarrier group, etc.). The different groups of adjacent subcarriers associated with each user may be considered as corresponding channels of a plurality of channels, all of which are the available subcarriers for OFDM signaling.

In general, each communication device described herein may be configured to include a processor and the communication interface configured to process received OFDM or OFDMA symbols and / or frames, and such OFDM or OFDMA symbols and / or frames.

With respect to an OFDMA symbol and / or packet / frame format, a general format of an OFDMA packet / frame may include at least one Short Training Field (STF), at least one Long Training Field (LTF) field "), at least one signal field (SIG) implemented within a preamble of the OFDMA packet, followed by at least one data field or payload of the OFDMA packet / frame. In an example of an OFDMA packet / frame, the first at least one field comprises a first short training field (STF) followed by a first long training field (LTF) followed by at least one first signal field (SIG) and the second comprises at least one field a second STF followed by a second LTF followed by at least one second SIG, followed by at least one data field or payload of the OFDMA packet / frame. In another example of an OFDMA packet / frame, the first at least one field comprises a short training field (STF) followed by a first long training field (LTF) followed by at least one first signal field (SIG) and the second comprises at least one field a second LTF followed by at least one second SIG, followed by at least one data field or payload of the OFDMA packet / frame. It should be noted that other OFDMA frame / packet formats include one or more legacy fields for use by other devices, including those associated with earlier versions of communication standards, protocols, and / or recommended practices, including these with respect to various versions, changes, and extensions of IEEE 802.11 are compliant. Often such old data fields are in Diagrams, which include the prefix "L" indicating "legacy" or "legacy".

It should also be noted that multiple combinations between devices may be performed using an OFDMA packet format, which may include two or more OFDMA symbols, within a multiple user (MU) transmission of two or more devices. As mentioned above, the specific contents of data and a copy or repetition of the data contained in one or more subcarriers may be of some sort. In a specific example, the data includes a long training field (LTF) and the copy or repetition of the data is a copy of that LTF.

As described herein, this disclosure describes new mechanisms to enable a wireless communication device (eg, a receiver, a transmitter, an access point (AP), a wireless station (STA), etc.) to receive packets from a user and / or multiple users Simultaneously receive users for use in estimating the Carrier Frequency Offset (CFO) from each of these. In some examples, a wireless communication device is configured to receive only packets from a wireless communication device or source at a time, and the packet structure of such received packets is constructed such that a CFO estimate based on the first field of the short training field (STF ) and long training field (LTF).

This disclosure presents a new approach that uses a common data structure from a corresponding user or wireless communication device that is repeated at least twice in a common at least one subcarrier. In one example, the data structure includes an LTF structure that is repeated twice. It should be noted, however, that any type of data structure may be used. Likewise, this structure assigns a different subset of the tones or subcarriers to each wireless communication device or users (for example, a subset of subcarriers could have at least one subcarrier for each corresponding user, an adjacent set of tones, or a non-contiguous, distributed, non-overlapping set of tones for each corresponding user, etc.).

A suitable CFO estimate tailored for a maximum range (with possibly reduced accuracy) is used using two or more OFDMA symbols arranged as close as possible (for example, two OFDMA symbols related to one another) Time adjacent, consecutive and adjacent, or reasonably close to each other in a time with respect to some parameters). For two OFDM symbols separated by a time period T [s], the maximum theoretical CFO correction range is then 1 / 2T [Hz].

A suitable CFO estimate tailored for accuracy or maximum accuracy (with possibly reduced area) is employed using two or more OFDMA symbols that are relatively far away (for example, one or more) for accuracy intervening symbols between them). An appropriate OFDMA symbol length is employed to provide a design of at least two OFDM symbol lengths that can be supported (for example, 4 microseconds (μs) and 16 μs that affect estimation range and accuracy).

To provide these design considerations, a flexible structure is proposed in which two or more OFDMA symbols (eg, LTF symbols in some examples) are placed such that the required range and accuracy are met. Likewise, this disclosure proposes to allow a wireless communication device that receives transmissions simultaneously to specify in a trigger frame the exact number and location of the identical OFDMA symbols (eg, LTFs) that are used, so that the optimal configuration can be used, depending on the symbol length, the required accuracy (a higher number of spatial streams or higher MCS require greater accuracy) and the required range.

Several of the following diagrams depict various examples that may include data or copies or repeats of data within particular subcarriers of different OFDMA symbols for use in performing a CFO estimation. A given device may include the data (for example, D1, D2, D3, D4, etc.) and copies of the data (for example, CD1, CD2, CD3, CD4, etc.) from the plurality of wireless communication devices (for example, as W1, W2 , W3, W4, etc.) to determine any CFO associated with these devices.

5A FIG. 12 is a diagram illustrating an example 501 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform carrier frequency offset estimation (CFO estimation). This diagram shows first data (D1) of a first one wireless communication device (W1) and a copy of the first data (CD1) of W1 contained within a first at least one subcarrier within two consecutive and adjacent symbols, and also showing second data (D2) of a second wireless communication device (W2) and a copy of the second data (CD2) of W2 contained within a second at least one subcarrier within these two consecutive and adjacent symbols.

5B FIG. 12 is a diagram illustrating another example 502 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. This diagram shows D1 and CD1 of W1 included within a first at least one subcarrier within two symbols that are not immediately consecutive and adjacent, such that one or more intervening symbols are placed between them, and also shows D2 and CD2 of FIG W2 contained within a second at least one subcarrier within these same two symbols.

5C FIG. 12 is a diagram illustrating another example 503 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. This diagram shows D1 and CD1 of W1 contained within a first at least one subcarrier within two consecutive and adjacent symbols, and third data (D3) of W1 contained within the first at least one subcarrier within a following third symbol. This diagram shows D2 and CD2 of W2 contained within a second at least one subcarrier within two consecutive and adjacent symbols, and fourth data (D4) of W2 contained within the second at least one subcarrier within the following third symbol.

5D FIG. 12 is a diagram illustrating another example 504 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. This diagram shows D1 and CD1 of W1 contained within a first at least one subcarrier within two consecutive and adjacent symbols, and D3 of W2 (note: not W1 in this diagram) within the first at least one subcarrier within a following third one Symbols are included. This diagram shows D2 and CD2 of W2 contained within a second at least one subcarrier within two consecutive and adjacent symbols, and D4 of W1 (note: not W2 in this diagram) within the second at least one subcarrier within the following third Symbols are included. As can be seen in this diagram, the same at least one subcarrier may be used for data from different devices at different times. Generally speaking, the various subcarriers may be assigned in a nested manner so that any given subcarrier may be assigned to different facilities for different symbols and at different times.

5E FIG. 12 is a diagram illustrating another example 505 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. In the first and second symbols, this diagram shows D1 and CD1 of W1 included within a first at least one subcarrier, and D2 and CD2 of W2 included within a second at least one subcarrier. In a third symbol, this diagram shows D3 of W1 in a third at least one sub-carrier and D4 of W2 in a fourth at least one sub-carrier. It should be noted that the third and fourth at least one subcarriers are not the same as either the first or second at least one subcarrier. Generally speaking, subcarrier allocation for data from different devices may be adaptively changed for different symbols at different times. It should be noted that a given subcarrier may be used for data from more than one device.

5F FIG. 12 is a diagram illustrating another example 506 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. In the first and second symbols, this diagram shows D1 and CD1 of W1 included within a first at least one subcarrier, and D2 and CD2 of W2 included within a second at least one subcarrier. Then, after one or more intervening symbols, a third symbol also includes CD1 of W1 contained within the first at least one subcarrier, and CD2 of W2 contained within the second at least one subcarrier. In this diagram, the icon includes 2 a copy or repetition of at least D1 of W1 and D2 of W2 in the first and second at least one sub-carrier, and then includes symbol 3 that of symbol 2 is separated by one or more intervening symbols, as well as a copy or repetition of at least D1 of W1 and D2 of W2 in the first and second at least one subcarriers.

In certain of the following diagrams, an empty block shown within a given symbol may indicate any desired data or may also be empty. In general, each empty block may include any desired data or no data or information.

6A FIG. 13 is a diagram illustrating another example 601 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. In this diagram, a first symbol D1 of W1 in a first comprises at least one subcarrier and D2 of W2 in a second at least one subcarrier. The first symbol also includes D3 of W2 in a third at least one subcarrier and D4 of W2 in a fourth at least one subcarrier. A second symbol comprises CD1 of W1 in the first at least one subcarrier and CD3 of W2 in the third at least one subcarrier. A third symbol comprises CD2 of W1 in the second at least one subcarrier and CD4 of W2 in the fourth at least one subcarrier. The first, second and third symbols are all consecutive and adjacent to each other as shown in the diagram.

6B FIG. 12 is a diagram illustrating another example 602 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. This diagram includes a similar format to Example 601 of FIG 6A with at least one difference that one or more intervening symbols are included between the second symbol and the third symbol.

6C FIG. 12 is a diagram illustrating another example 603 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. In this diagram, a first symbol D1 of W1 in a first comprises at least one subcarrier and D2 of W1 in a second at least one subcarrier. The first symbol also includes D3 of W2 in a third at least one subcarrier and D4 of W2 in a fourth at least one subcarrier. The first symbol also includes D5 of W3 in a fifth at least one subcarrier and D6 of W3 in a sixth at least one subcarrier.

A second symbol comprises CD1 of W1 in the first at least one subcarrier, CD3 of W2 in the third at least one subcarrier and CD5 of W3 in the fifth at least one subcarrier. A third symbol comprises CD2 of W1 in the second at least one subcarrier, CD4 of W2 in the fourth at least one subcarrier and CD6 of W6 in the sixth at least one subcarrier. The first, second and third symbols are all consecutive and adjacent to each other as shown in the diagram.

6D FIG. 12 is a diagram illustrating another example 604 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. This diagram includes a similar format to Example 603 of FIG 6C with at least one difference that one or more intervening symbols are included between the second symbol and the third symbol.

7A FIG. 12 is a diagram illustrating another example 701 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. In this diagram, a first symbol D1 of W1 in a first comprises at least one subcarrier, D2 of W1 in a second at least one subcarrier, and D3 of W1 in a third at least one subcarrier. The first symbol also includes D4 of W2 in a fourth at least one subcarrier, D5 of W2 in a fifth at least one subcarrier and D6 of W2 in a sixth at least one subcarrier. A second symbol comprises CD1 of W1 in the first at least one subcarrier and CD4 of W2 in the fourth at least one subcarrier. A third symbol comprises CD2 of W1 in the second at least one subcarrier and CD5 of W2 in the fifth at least one subcarrier. A fourth symbol comprises CD3 of W1 in the third at least one subcarrier and CD6 of W2 in the sixth at least one subcarrier.

7B Figure 13 is a diagram illustrating another example 702 of OFDMA symbols received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. This diagram includes a similar format to Example 701 of FIG 7A with at least one difference that one or more intervening symbols between the second symbol and the third symbol and also one or more other intervening symbols between the third symbol and the fourth symbol are included.

It should be noted that other examples have a similar format to example 701 of FIG 7A with at least one difference that one or more intermediate symbols are included between the third symbol and the fourth symbol, but that the second symbol and the third symbol are consecutive and adjacent to each other. Another example may be a similar format to Example 701 of FIG 7A comprise, with at least one difference, one or more intervening symbols between the second symbol and the third symbol, but that the third symbol and the fourth symbol are consecutive and adjacent to one another.

In the above examples, generally speaking, when the repeated data of a symbol is far from its first / original occurrence in the packet / frame, this serves for better accuracy but a lower dynamic range (e.g., maximum CFO estimation range with possibly reduced Accuracy). Alternatively, if the repeated data of a symbol is placed very close to each other (for example adjacent and consecutive) in the packet / frame, this serves a lower accuracy, but a better or maximum range (for example, maximum CFO estimation accuracy with possibly smaller range). , However, as shown above, some examples optimize both accuracy and range in a CFO estimate by including data.

As mentioned above, different types of data may be used by multiple devices or users to perform a CFO estimation. Some of the following examples use LTFs as the type of data of multiple users modulated within the various subcarriers. It should be noted that, as shown in many of these diagrams, an LTF includes information from multiple users (for example, section of user # 1, section of user # 2, etc.) so that the subcarriers are split and assigned among different users are.

8A Figure 13 is a diagram illustrating an example 801 of OFDMA symbols comprising long training fields (LTFs) received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. With respect to the trigger frame option as described above, such an OFDMA frame may be implemented as a trigger frame used to initiate an uplink (UL) or multiple user (MU) frame (e.g., a UL frame). Orthogonal Frequency Division Multiple Access (OFDMA) frame or UL-MU frame) which signals the presence and location of the second, third and several LTF symbols. In the diagram, three LTF symbols are shown (for example, each represented as LTF1 repeated once in a consecutive or adjacent symbol or in a subsequent symbol separated by at least one intervening symbol, or twice in the successive or adjacent one Symbol is repeated and also in the subsequent symbol separated by at least one intermediate symbol). This example 801 can be implemented as two adjacent symbols. Alternatively, this example 801 may be implemented as two adjacent symbols and a third symbol separated by at least one intermediate symbol. In general, the second, third, and higher LTF repetition symbols in various examples can be placed in any gap relative to each other.

1. (1) LTF für andere räumliche Streams: in einer Mehrfachnutzer-MIMO-Anwendung, müssen mehrere LTFs gesendet werden, um alle räumlichen Streams zu schätzen. In diesem Fall teilen die mehreren LTFs 1 bis LTF4 (LTF1-4) Töne für die unterschiedlichen drahtlosen Kommunikationseinrichtungen oder Benutzer untereinander auf; und/oder
2. (2) das Signalfeld SIG: in diesem Fall wird ein grober CFO verwendet (zum Beispiel der, der einen maximalen Bereich ermöglicht), um das SIG-Feld zu schätzen, das einen relativ niedrigen Modulationscodiersatz (MCS, „modulation coding set“) verwendet (zum Beispiel MCS0), und dann werden ein oder mehrere extra LTFs verwendet, um eine CFO-Genauigkeit für die Nutzlast zu verbessern.

8B FIG. 12 is a diagram illustrating another example 802 of OFDMA symbols that include LTFs received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. The gap between the repeated LTF symbols shown in this diagram can be used for one or more of the following:

1. (1) LTF for other spatial streams: in a multi-user MIMO application, multiple LTFs must be sent to estimate all spatial streams. In this case, the multiple LTFs share 1 to LTF4 (LTF1-4) tones for the different wireless communication devices or users among each other; and or
2. (2) the signal field SIG: in this case, a coarse CFO is used (for example, the one allowing a maximum range) to estimate the SIG field using a relatively low Modulation Coding Set (MCS) (for example, MCS0) and then one or more extra LTFs are used to improve CFO accuracy for the payload.

8C FIG. 12 is a diagram illustrating another example 803 of OFDMA symbols comprising LTFs received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. In this diagram, it should be noted that the SIG field can also use the following structure for UL MU (which is similar to UL OFDMA). In such an implementation, each SIG field of a wireless communication device / user is restricted to the audio or subcarrier allocation used for the wireless communication device or the user during LTF1. Then the payload is shared across the bandwidth (for example, via the subcarriers assigned for users # 1-4).

9A FIG. 12 is a diagram illustrating another example 901 of OFDMA symbols comprising LTFs received from other wireless communication devices for use by a wireless communication device to perform a CFO estimation. If both maximum range and maximum accuracy are desired or required in a particular implementation, two (or more) extra LTF symbols can be used for CFO estimation in an optimized solution. However, a more efficient design is provided with reference to this diagram where only one extra LTF is used instead of two.

This can be achieved by repeating half of the tones or subcarriers for each wireless communication device or users in the adjacent LTF and repeating the other half of subcarriers in the far-flung LTF. The diagram shows an example of three wireless communication devices or users (for example, WDEV1, WDEV2 and WDEV3 or user # 1, user # 2 and user # 3), the four LTFs to estimate channels, a coarse (maximum range) frequency estimate, and a use fine (maximum accuracy) frequency estimation and similarly extend to any number of wireless communication devices / users and spatial streams.

In the diagram, each column shows an LTF and shows each row of groups of tones or subcarriers (for example, a group may be contiguous as shown, or not contiguous in an alternative implementation).

The symbols "*", "◯" and "Δ" indicate wireless communication devices or users. Each wireless communication device or user is assigned two half-groups in each LTF as shown. With four LTFs, each communication device or user is assigned to each subcarrier so that channels can be estimated by each communication device or user. The upper halves of LTF1 and LTF2 (red color) can be used for a rough frequency estimation. The lower halves of LTF1 and LTF4 (blue color) can be used for a fine frequency estimation.

As can be seen with respect to the many different examples and embodiments described herein, dynamic allocation of subcarriers to different devices and / or users may be made with respect to different symbols and as a function of time. The same subcarrier may be used to transmit data for two or more different devices and / or users. Likewise, different degrees of spacing between symbols may be made to optimize a range and / or accuracy of a CFO estimate. Any desired combination of consecutive or adjacent symbols or symbols separated by one or more intervening symbols may be used in various embodiments and examples to optimize various degrees of range and / or accuracy. It should also be noted that some implementations may weight the consideration of one domain relatively more heavily than the consideration of accuracy, while other implementations weight more accuracy than one domain.

9B Fig. 10 is a diagram illustrating an example 902 of processing data contained within an OFDMA symbol device to perform a CFO estimation. Regardless of the particular arrangement of data and copies / iterations of these data in various subcarriers in accordance with any of the various examples or embodiments described herein, a receiver device (W0) includes circuitry and capability for processing first data from a first transmitter device (FIG. D1 from W1) and a copy of this first data (CD1) from W1 to determine a carrier frequency (CF) of W1, and also second data from a second transmitter means (D2 from W2) and a copy of the second data (CD2) from W2 to determine a carrier frequency (CF) of W2. The receiver device (W0) also includes circuitry and ability to determine any CFO of W1 and any CFO of W2 based on the first and second Carrier frequencies of W1 and W2 and a frequency reference of the receiver device (W0).

9C FIG. 13 is a diagram illustrating another example 903 of processing data contained within an OFDMA symbol device to perform a CFO estimation. Regardless of the particular arrangement of data and copies / iterations of these data in various subcarriers in accordance with any of the various examples or embodiments described herein, a receiver device (W0) includes circuitry and capability for processing first data from a first transmitter device (FIG. D1 from W1) and a first copy of this first data (CD1) from W1 to an nth copy of this first data (CDn) from W1 to determine a carrier frequency (CF) of W1. The receiver device W0 comprises a circuit and an ability to process second data from an xth transmitter (D2 from Wx), a first copy of this second data (CD2) from Wx to an mth copy of this second data (CDm) from Wx to determine a carrier frequency (CF) of W2. The receiver device (W0) also includes circuitry and capability for determining any CFO of W1 and any CFO of Wx based on the first and xth carrier frequencies of W1 and Wx and a frequency reference of the receiver device (W0).

10A is a diagram illustrating an embodiment of a method 1001 for execution by one or more wireless communication devices. The procedure 1001 begins receiving, via a communication interface of the wireless communication device, a first orthogonal frequency division multiple access (OFDMA) symbol, the first data from a first other wireless communication device (W1) modulated on a first at least one sub-carrier and second data from a second one other wireless communication device (W2) modulated on a second at least one sub-carrier comprises (block 1010 ).

The procedure 1001 continues by receiving, via the communication interface of the wireless communication device, a second OFDMA symbol containing a copy of the first data from the first other wireless communication device (W1) modulated on the first at least one sub-carrier and a copy of the second one Comprises data from the second other wireless communication device (W2) modulated on the second at least one subcarrier (block 1020 ).

The procedure 1001 then operates by processing the first data and the copy of the first data to determine a first carrier frequency associated with the first other wireless communication device (W1) (block 1030). The procedure 1001 then proceeds by processing the second data and the copy of the second data to determine a second carrier frequency associated with the second other wireless communication device (W2) (Block 1040 ).

The procedure 1001 then operates by determining a first carrier frequency offset (CFO) associated with the first other wireless communication device (W1) based on the first carrier frequency and a frequency reference associated with the wireless communication device comprising the method 1001 performs (W0), is linked (block 1050 ). The method 1001 continues by determining a second CFO associated with the second other wireless communication device (W2) based on the second carrier frequency and the frequency reference associated with the wireless communication device using the method 1001 performs (W0), is linked (block 1060 ).

It should be noted that as soon as any CFOs of the first and second wireless communication devices (W1 and W2) through the wireless communication device, the process 1001 performs (W0), the wireless communication device that determines the method 1001 (W0), these CFOs may use to modify or adapt any communications intended or received for the first and second wireless communication devices (W1 and W2) based on those CFOs.

10B FIG. 10 is a diagram illustrating another embodiment of a method 1002 for execution by one or more wireless communication devices. The procedure 1002 begins with generating a subcarrier allocation frame specifying subframes for use by first and second wireless communication devices (W1 and W2) in a subsequent communication (block 1011 ). The procedure 1002 continues by transmitting the generated subcarrier allocation frame to the first and second wireless communication devices (W1 and W2) (Block 1021 ). The procedure 1002 then operates by receiving two or more OFDMA symbols from the first and second wireless communication devices (W1 and W2) containing data and copies or repetitions of that data based on the subcarrier allocation frame (Block 1031 ).

The procedure 1002 then continues by processing the data and the copies of the data to determine the carrier frequencies of the first and second wireless communication devices (W1 and W2) (Block 1041 ). The procedure 1002 then operates by determining any CFOs of the first and second wireless communication devices (W1 and W2) based on the carrier frequencies of the first and second wireless communication devices (W1 and W2) (Block 1051 ).

It should be appreciated that the various operations and functions described herein within various methods within a wireless communication device (such as, for example, by the processor 330 , the communication interface 320 and a memory 340 as related to 3A described) and / or other components can be carried out in this. In general, a communication interface and a processor in a wireless communication device may perform such operations.

Examples of some components may include one or more baseband processing modules, one or more media access control (MAC) layer components, one or more physical layer (PHY) components, and / or other components, and so on. For example, such a processor may perform baseband operations and may operate in conjunction with a radio, an analog front-end (AFE), and so on. The processor may generate such signals, packets, frames, and / or equivalents, etc. as described herein, as well as perform various operations described herein and / or their respective equivalents.

In some embodiments, such baseband processing module and / or processing module (which may be implemented in the same device or in separate devices) may perform such processing to transmit signals for transmission to other wireless communication devices using any number of radios and antennas to create. In some embodiments, such processing is performed cooperatively by a processor in a first device and another processor within a second device.

In other embodiments, such processing is performed entirely by a processor within a device.

As used herein, the terms "substantially" and "approximately" provide an industry accepted tolerance for the corresponding term and / or elemental relativity. Such an industry-accepted tolerance ranges from less than one percent to 50 percent, and includes, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and / or thermal noise. Such a relativity between elements ranges from a few percent difference to magnitude differences. As used herein, the terms "configured to," "operatively coupled to," "coupled to," and / or "coupling" include direct coupling between elements and / or indirect coupling between elements via an intervening element (eg, an element including, but not limited to, a component, an element, a circuit, and / or a module), where, for an example of indirect coupling, the intermediate element does not modify the information of a signal, but its current level, voltage level, and / or performance level. As further used herein, a derived coupling (that is, where one element is coupled to another element by an inference) includes direct and indirect coupling between two elements in the same manner as "coupled". As may also be used herein, the term "configured to," "operable," "coupled," or "operably coupled" indicates that an element includes one or more power connections, input (s), output (s), and so forth ., in order to perform one or more of their respective functions when activated, and may further comprise a derived coupling to one or more other elements. As further used herein, the term "associated with" includes direct and / or indirect coupling of separate elements and / or an element embedded within another element.

As used herein, the term "positive comparison" or equivalent indicates that a comparison between two or more elements, signals, etc., gives a desired relationship. If, for example, the desired relationship is that signal 1 has a larger magnitude than signal 1, a positive comparison can be achieved if the magnitude of signal 1 is greater than that of signal 2 , or if the magnitude of signal 2 is less than that of signal 1 ,

As also used herein, the terms "processing module", "processing circuit", "processor" and / or "processing unit" may be a single processing device or a plurality of processing devices. Such a processing device may be Be a microprocessor, a microcontroller, a digital signal processor, a microcomputer, a central processing unit, a field programmable gate array, a programmable logic device, a state machine, a logic circuit, an analog circuit, a digital circuit and / or any device which signals based on a hard-coding of Circuitry and / or operational instructions manipulated. The processing module, module, processing circuit and / or processing unit may be or further comprise a memory and / or an integrated memory element comprising a single memory device, a plurality of memory devices and / or an embedded circuit of another processing module, module, processing circuit and / or processing unit can be. Such a memory device may be read only memory, random access memory, volatile memory, nonvolatile memory, static memory, dynamic memory, flash memory, cache, and / or any device storing digital information. It should be noted that if the processing module, module, processing circuitry, and / or processing unit comprises more than one processing device, the processing devices may be centrally located (eg, coupled directly via a wired and / or wireless bus structure) or distributed (FIG. for example, cloud computing via an indirect link via a local area network and / or a wide area network). Further note that when the processing module, module, processing circuitry, and / or processing unit implement one or more of its functions via a state machine, analog circuitry, digital circuitry, and / or logic circuitry, the memory and / or the memory element that stores the corresponding operational instructions may be stored, internal or external to the circuit comprising the state machine, the analog circuit, the digital circuit and / or the logic circuit. Furthermore, it should be noted that the memory element may store hard-coded and / or operational instructions corresponding to at least some of the steps and / or functions illustrated in one or more of the figures, and the processing module, module, processing circuit or processing unit may execute them. Such a storage device or storage element may be included in an article of manufacture.

One or more embodiments of an invention have been described above with the aid of method steps representing the performance of specified functions and relationships thereof. The limitations and sequence of these functional design blocks and method steps have been arbitrarily defined herein for simplicity of description. Alternative limits and procedures can be defined as long as the specified functions and relationships are properly performed. Any such alternative limits or procedures are thus within the scope and spirit of the claims. Furthermore, limits of these functional design blocks have been arbitrarily defined for simplicity of description. Alternative limits can be defined as long as certain significant functions can be adequately performed. Likewise, flowchart blocks herein may also be arbitrarily defined to represent certain significant functionality. To the extent used, the flowchart block boundaries and sequence could be otherwise defined and still perform the particular significant functionality. Such alternative definitions of both functional design blocks and flowchart blocks and sequences are thus within the scope and spirit of the claimed invention. Those skilled in the art will also appreciate that the functional design blocks and other illustrative blocks, modules, and components herein may be implemented as illustrated or discrete components, application specific integrated circuits, processors executing appropriate software, and the like, or any combination thereof.

The one or more embodiments are used herein to illustrate one or more aspects, one or more features, one or more concepts, and / or one or more examples of the invention. A physical embodiment of a device, an article of manufacture, a machine, and / or a process may include one or more of the aspects, features, concepts, examples, etc. described with respect to one or more of the embodiments discussed herein , Furthermore, the embodiments from figure to figure may include the same or similar functions, steps, modules, etc., using the same or different reference numbers, and as such, the functions, steps, modules, etc. may have the same or similar functions, steps, modules etc. or different.

Unless otherwise specified, signals to, from and / or between elements in a figure of any of the figures presented herein may be analog or digital, time continuous or time discrete and unbalanced or differential. For example, when a signal path is shown as an unbalanced path, it also represents a differential signal path. Similarly, when a signal path is shown as a differential path, it also represents an unbalanced signal path. While one or more particular architectures are described herein, Similarly, other architectures may be implemented that use one or more data buses that are not explicitly shown, direct connectivity between elements, and / or indirect coupling between other elements, as recognized by those skilled in the art.

The term "module" is used in the description of one or more of the embodiments. A module includes a processing module, a processor, a functional block, hardware and / or memory that stores operational instructions for performing one or more functions that may be described herein. It should be noted that if the module is implemented via hardware, the hardware may operate independently and / or in conjunction with software and / or firmware. As also used herein, a module may include one or more sub-modules, each of which may be one or more modules.

While certain combinations of various functions and features of the one or more embodiments have been expressly described herein, other combinations of these features and functions are similarly possible. The present disclosure of an invention is not limited to the particular examples disclosed herein and expressly encompasses these other combinations.

A wireless communication device includes circuitry and ability to make an estimate of carrier frequency offset (CFO) based on signals received from one or more other wireless communication devices. In one implementation of Orthogonal Frequency Division Multiple Access (OFDMA), the wireless communication device receives two or more OFDMA symbols from first and second other wireless communication devices that include data and a copy / repeat of that data from each of the corresponding first and second other wireless communication devices within one or more several specified subcarriers. The sub-carrier assignment for the first and second other wireless communication devices is made such that the first wireless communication device transmits first data and the copy of the first data using a first at least one sub-carrier, and the second wireless communication device transmits second data and the copy of these second data transmits using a second at least one subcarrier.

Claims (18)

A wireless communication device, comprising: a communication interface; and a processor, wherein the processor and the communication interface are configured to: receive a first orthogonal frequency division multiple access (OFDMA) symbol, the first data from a first other wireless communication device modulated on a first at least one subcarrier, and second data from a second other wireless communication device modulated on a second at least one subcarrier; receive a second OFDMA symbol which is a copy of the first data from the first other wireless communication device modulated on the first at least one subcarrier, and a copy of the second data from the second other wireless communication device that is on the second at least one Subcarriers are modulated; processing the first data and the copy of the first data to determine a first carrier frequency associated with the first other wireless communication device; processing the second data and the copy of the second data to determine a second carrier frequency associated with the second other wireless communication device; determine a first carrier frequency offset (CFO) associated with the first other wireless communication device based on the first carrier frequency and a frequency reference associated with the wireless communication device; determine a second CFO associated with the second other wireless communication device based on the second carrier frequency and the frequency reference associated with the wireless communication device; receive the first OFDMA symbol, which also comprises third data from the first other wireless communication device modulated on a third at least one subcarrier and fourth data from the second other wireless communication device modulated on a fourth at least one subcarrier ; receive a third OFDMA symbol which is a copy of the third data from the first other wireless communication device modulated on the third at least one subcarrier, and a copy of the fourth data from the second other wireless communication device that on the fourth at least one Subcarriers are modulated, wherein the second OFDMA symbol and the third OFDMA symbol are separated by at least one other OFDMA symbol; processing the first data, the copy of the first data, the third data and the copy of the third data to determine the first carrier frequency associated with the first other wireless communication device; and process the second data, the copy of the second data, the fourth data and the copy of the fourth data to determine the second carrier frequency associated with the second other wireless communication device. Wireless communication device according to Claim 1 wherein the processor and the communication interface are further configured to: generate a subcarrier allocation frame including the first at least one subcarrier for modulating the first data and the copy of the first data by the first other wireless communication device and the second at least one subcarrier for modulation the second data and the copy of the second data are specified by the second other wireless communication device within the first OFDMA symbol and the second OFDMA symbol; and transmit the sub-carrier assignment frame to the first other wireless communication device and the second other wireless communication device before receiving the first OFDMA symbol and the second OFDMA symbol. Wireless communication device according to Claim 2 wherein the processor and the communication interface are further configured to: generate the subcarrier allocation frame also including at least one of a third at least one subcarrier for modulating third data by the first other wireless communication device or a fourth at least one subcarrier for modulating fourth data specified by the second other wireless communication device within a third OFDMA symbol; and transmit the subcarrier allocation frame to the first other wireless communication device and the second other wireless communication device prior to receiving the first OFDMA symbol, the second OFDMA symbol, and the third OFDMA symbol. Wireless communication device according to Claim 2 wherein the processor and the communication interface are further configured to: generate the subcarrier allocation frame also including at least one of the first at least one subcarrier for modulating third data by the second other wireless communication device or the second at least one subcarrier to modulate fourth data specified by the first other wireless communication device within a third OFDMA symbol; and transmit the subcarrier allocation frame to the first other wireless communication device and the second other wireless communication device prior to receiving the first OFDMA symbol, the second OFDMA symbol, and the OFDMA symbol. Wireless communication device according to Claim 1 wherein the processor and the communication interface are further configured to: an OFDMA packet comprising the first OFDMA symbol and the second OFDMA symbol within a multiple user (MU) transmission from the first other wireless communication device and the second other communication device to receive. Wireless communication device according to Claim 5 wherein the OFDMA packet comprises a first long training field (LTF) based on the first OFDMA symbol and a second LTF based on the second OFDMA symbol. Wireless communication device according to Claim 1 wherein the wireless communication device is an access point (AP) and the first other wireless communication device is a first wireless station (STA) and the second other wireless communication device is a second STA. A wireless communication device, comprising: a communication interface; and a processor, wherein the processor and communication interface are configured to: receive a first orthogonal frequency division multiple access (OFDMA) symbol, the first data from a first other wireless communication device modulated on a first at least one subcarrier, second data from the first other wireless communication device modulated on a second at least one sub-carrier, third data from a second other wireless communication device modulated on a third at least one subcarrier, and fourth data from the second other wireless communication device that on a fourth at least a subcarrier are modulated; receive a second OFDMA symbol comprising a copy of the first data from the first other wireless communication device modulated on the first at least one subcarrier and a copy of the third data from the second other wireless communication device modulated on the third at least one sub-carrier comprises; receive a third OFDMA symbol which is a copy of the second data from the first other wireless communication device modulated on the second at least one subcarrier and a copy of the fourth data from the second other wireless communication device that on the fourth at least one Subcarriers are modulated, wherein the second OFDMA symbol and the third OFDMA symbol are separated by at least one other OFDMA symbol; processing the first data, the copy of the first data, the second data and the copy of the second data to determine a first carrier frequency associated with the first other wireless communication device; processing the third data, the copy of the third data, the fourth data and the copy of the fourth data to determine a second carrier frequency associated with the second other wireless communication device; determine a first carrier frequency offset (CFO) associated with the first other wireless communication device based on the first carrier frequency and a frequency reference associated with the wireless communication device; and determine a second CFO associated with the second other wireless communication device based on the second carrier frequency and the frequency reference associated with the wireless communication device. Wireless communication device according to Claim 8 wherein the processor and the communication interface are further configured to: generate a subcarrier allocation frame including the first at least one subcarrier for modulating the first data and the copy of the first data by the first other wireless communication device, the second at least one subcarrier for modulation the second data and the copy of the second data by the first other wireless communication device, the third at least one subcarrier for modulating the third data and the copy of the third data by the second other wireless communication device and the fourth at least one subcarrier for modulating the fourth data and specifying the copy of the fourth data by the second other wireless communication device within the first OFDMA symbol, the second OFDMA symbol, and the third OFDMA symbol; and transmit the subcarrier allocation frame to the first other wireless communication device and the second other wireless communication device prior to receiving the first OFDMA symbol, the second OFDMA symbol, and the third OFDMA symbol. Wireless communication device according to Claim 8 wherein the processor and the communication interface are further configured to: an OFDMA packet comprising the first OFDMA symbol and the second OFDMA symbol within a multiple user (MU) transmission from the first other wireless communication device and the second other communication device to receive. Wireless communication device according to Claim 10 wherein the OFDMA packet comprises a first long training field (LTF) based on the first OFDMA symbol, a second LTF based on the second OFDMA symbol, and a third LTF based on the third OFDMA symbol includes. Wireless communication device according to Claim 8 wherein the wireless communication device is an access point (AP) and the first other wireless communication device is a first wireless station (STA) and the second other wireless communication device is a second STA. A method of execution by a wireless communication device, the method comprising: receiving, via a communication interface of the wireless communication device, a first orthogonal frequency division multiple access (OFDMA) symbol, the first data from a first other wireless communication device modulated on a first at least one subcarrier and second data from a second other wireless communication device modulated on a second at least one subcarrier; Receiving, via the communication interface of the wireless communication device, a second OFDMA symbol containing a copy of the first data from the first other wireless communication device modulated on the first at least one subcarrier and a copy of the second data from the second other wireless communication device which are modulated on the second at least one subcarrier comprises; Processing the first data and the copy of the first data to determine a first carrier frequency associated with the first other wireless communication device; Processing the second data and the copy of the second data to a second carrier frequency determine which is associated with the second other wireless communication device; Determining a first carrier frequency offset (CFO) associated with the first other wireless communication device based on the first carrier frequency and a frequency reference associated with the wireless communication device; Determining a second CFO associated with the second other wireless communication device based on the second carrier frequency and the frequency reference associated with the wireless communication device; Receiving, via the communication interface of the wireless communication device, the first OFDMA symbol also including third data from the first other wireless communication device modulated on the third at least one subcarrier and fourth data from the second other wireless communication device based on a fourth one at least one subcarrier are modulated comprises; Receiving, via the communication interface of the wireless communication device, a third OFDMA symbol containing a copy of the third data from the first other wireless communication device modulated on the third at least one subcarrier and a copy of the fourth data from the second other wireless communication device comprising at least one sub-carrier modulated on the fourth, the second OFDMA symbol and the third OFDMA symbol being separated by at least one other OFDMA symbol; Processing the first data, the copy of the first data, the third data and the copy of the third data to determine the first carrier frequency associated with the first other wireless communication device; and processing the second data, the copy of the second data, the fourth data and the copy of the fourth data to determine the second carrier frequency associated with the second other wireless communication device. Method according to Claim 13 , further comprising: generating a subcarrier allocation frame including the first at least one subcarrier for modulating the first data and the copy of the first data by the first other wireless communication device and the second at least one subcarrier for modulating the second data and the copy of the second data through the subcarrier second other wireless communication device specified within the first OFDMA symbol and the second OFDMA symbol; and transmitting, via the communication interface of the wireless communication device, the sub-carrier assignment frame to the first other wireless communication device and the second other wireless communication device before receiving the first OFDMA symbol and the second OFDMA symbol. Method according to Claim 14 , further comprising: generating the sub-carrier assignment frame also including at least one of the first at least one sub-carrier for modulating the third data by the second other wireless communication device or the second at least one sub-carrier to modulate fourth data by the first other wireless communication device within a third OFDMA Symbols specified; and transmitting, via the communication interface of the wireless communication device, the sub-carrier assignment frame to the first other wireless communication device and the second other wireless communication device before receiving the first OFDMA symbol, the second OFDMA symbol and the third OFDMA symbol. Method according to Claim 13 , further comprising: receiving, via the communication interface of the wireless communication device, an OFDMA packet comprising the first OFDMA symbol and the second OFDMA symbol within a multiple user (MU) transmission from the first other wireless communication device and the second one other communication device. Method according to Claim 16 wherein the OFDMA packet comprises a first long training field (LTF) based on the first OFDMA symbol and a second LTF based on the second OFDMA symbol. Method according to Claim 13 wherein the wireless communication device is an access point (AP) and the first other wireless communication device is a first wireless station (STA) and the second other wireless communication device is a second STA.

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