MECHANISM FOR DETECTING ATTACKS ON FREQUENCY OFFSET IN A WIRELESS NETWORK

This disclosure describes systems, methods, and devices for a mechanism for detecting attacks on frequency offset in a wireless network. A device may receive a packet from a reflector device, wherein the packet comprises an access code and a coded sequence of bits. The device may also receive a tone signal from the reflector device. The device may then calculate a first frequency offset estimation associated with the packet and calculate a second frequency offset estimation associated with the tone signal. The device may then calculate a difference between the first frequency offset estimation and the second frequency offset estimation. The device may further identify an allowable threshold range of the difference.

TECHNICAL FIELD

This disclosure generally relates to systems and methods for wireless communications and, more particularly, to a mechanism for detecting attacks on frequency offset in a Wireless Network.

BACKGROUND

Wireless devices are becoming widely prevalent and are increasingly requesting access to wireless channels. The Institute of Electrical and Electronics Engineers (IEEE) is developing one or more standards that utilize Orthogonal Frequency-Division Multiple Access (OFDMA) in channel allocation.

DETAILED DESCRIPTION

Each wireless network may facilitate certain Bluetooth® features, such as High Accuracy Distance Measurement (HADM). HADM may be used to measure a distance between two devices configured to use Bluetooth® technology. For example, a first device that initiates a Bluetooth® connection to a second device may be known as an initiator device, while the second device may be known as the reflector device.

The present mechanism for measuring a distance between two devices is to transmit a tone signal from the reflector device to the initiator device. The initiator device may calculate a phase of the tone signal when it receives the tone signal, and an initial phase of the tone signal at the time of transmission may be further made known to the initiator device. For example, the initiator device may listen to its own previous transmission and record itself in order to know the initial phase of the tone signal. Other methods may also be used to ensure that the initial phase of the tone signal at the time of transmission is known to the initiator device. A phase difference can thus be calculated as the difference between the phase of the tone signal when the initiator device receives the tone signal and the initial phase of the tone signal. The phase difference may then be used to measure the distance between the initiator device and the reflector device.

Currently, in order to calculate a phase of the tone signal when the initiator device receives the tone signal, the frequency of the tone signal must be known. If the frequency has been offset (e.g., interfered with), then the phase calculation may deviate from the actual phase of the tone signal when the initiator device receives the tone signal. The deviation in the phase calculation may then result in an inaccurate measurement of the distance between the initiator device and the reflector device, since distance is directly related to the phase difference.

However, because tone signals may be vulnerable to interference, inaccuracies in distance measurement may arise due to interference that causes incorrect detection of a frequency used to transmit the tone signal, which may then result in distortion in the initiator device's calculation of the phase difference. Further, although frequency offsets naturally occur during HADM events, an inaccurate frequency offset estimation may then result in an inaccurate distance measurement. Interference may be deliberate or unintentional. For example, unintentional interference may include Wi-Fi signals in the surrounding area, other Bluetooth® devices in the surrounding area, or any other form of interference operating in a same frequency range of the tone signal. For example, one possible frequency range of the tone signal may be from 2.4 GHz to 2.4835 GHz. Further, deliberate interference may involve a hacker listening to Bluetooth® transmissions to discover the initiation of procedures associated with HADM events, and the hacker then transmitting additional tone(s) or whiteout signals in order to disrupt the distance measurement. As a result, because the current mechanism does not proactively detect if interference may have occurred before attempting the distance measurement, the distance measurement may be inaccurate if interference has occurred but was not detected.

It would thus be beneficial to replace the present mechanism for calculating a distance between two Bluetooth® devices with a mechanism that allows an initiator device to verify the absence of interference with the tone signal prior to proceeding with the distance calculation.

Since there is presently no mechanism for a Bluetooth® device to verify the absence of interference with the tone signal prior to proceeding with the distance calculation, the Bluetooth® device has no knowledge of whether interference has occurred. However, because of this lack of knowledge of whether interference has occurred, in some instances, the distance measurement may be inaccurate because the initiator device may incorrectly determine the frequency at which the tone signal is transmitted.

Example embodiments of the present disclosure relate to systems, methods, and devices for a mechanism for detecting attacks on frequency offset in a wireless network.

In one embodiment, an attack on frequency detection system may facilitate a mechanism for detecting attacks on frequency offset.

In one or more embodiments, a device can receive a packet from a reflector device, where the packet comprises an access code and a coded sequence of bits. The packet can be coded using Gaussian Frequency Shift Keying (GFSK). The device can be an initiator device. The initiator device and the reflector device can both be configured for Bluetooth® transmissions. Prior to the device receiving the packet from the reflector device, the device can have already synchronized to the reflector device by first sending a different packet comprising a preamble having an access code and a coded sequence of bits to the reflector device.

In one or more embodiments, the device can further receive a tone signal from the reflector device.

In one or more embodiments, the device can calculate a first frequency offset estimation associated with the packet. This can be done by calculating the frequency offset estimation of the coded sequence of bits.

In one or more embodiments, the device can calculate a second frequency offset estimation associated with the tone signal. For example, when the device receives the tone signal, it can sample the tone signal to calculate the second frequency offset estimation.

In one or more embodiments, the device can calculate a difference between the first frequency offset estimation and the second frequency offset estimation, and the device can identify an allowable threshold range of the difference. As an example, an allowable threshold range can include a range of up to 10 kHz. If the difference is determined to not be within the allowable threshold range, the tone signal can be flagged as having been interfered with. In such an instance, the device can then omit a subsequent frequency offset calculation and discontinue the High Accuracy Distance Measurement (HADM) event in order to prevent an inaccurate distance measurement. Interference with the tone signal can take the form of a transmission of an attack tone that is stronger than the tone signal. If the difference is determined to be within the allowable threshold range, the tone signal can be flagged as not having been interfered with. The distance between the device and the reflector device can then be calculated based at least in part on the difference.

The proposed solution enables a mechanism to provide Bluetooth® devices with a mechanism to accurately calculate a distance between two Bluetooth® devices. Such a mechanism not only ensures the accuracy of the distance calculations, but also eliminates wasteful distance calculations if the distance calculation is likely to be inaccurate. The proposed solution thus further enables a Bluetooth® device to better detect interference with Bluetooth® transmissions.

The above descriptions are for purposes of illustration and are not meant to be limiting. Numerous other examples, configurations, processes, algorithms, etc., may exist, some of which are described in greater detail below. Example embodiments will now be described with reference to the accompanying figures.

FIG. 1is a network diagram illustrating an example wireless network100of a system for detecting attacks on frequency offset, according to some example embodiments of the present disclosure. Wireless network100can include one or more user devices120(e.g.,122,124,126, or128), which may communicate in accordance with wireless standards, such as Bluetooth and the IEEE 802.11 communication standards, over network(s)130.

In some embodiments, the user devices120can include one or more computer systems similar to that of the functional diagram ofFIG. 5and/or the example machine/system ofFIG. 6.

One or more illustrative user device(s)120may be operable by one or more user(s)110. The user device(s)120(e.g.,122,124,126, or128) may include any suitable processor-driven user device including, but not limited to, a desktop user device, a laptop user device, a server, a router, a switch, an access point, a smartphone, a tablet, a wearable wireless device (e.g., a bracelet, a watch, glasses, a ring, etc.), and so forth.

Any of the user devices120(e.g.,122,124,126, or128) may be configured to communicate with each other and any other component of the wireless network100directly and/or via the one or more communications networks130, wirelessly or wired.

Any of the user devices120(e.g.,122,124,126, or128) may include one or more communications antennas. Communications antennas may be any suitable type of antenna corresponding to the communications protocols used by the user device(s)120. Some non-limiting examples of suitable communications antennas include Bluetooth antennas, Wi-Fi antennas, IEEE 802.11 family of standards compatible antennas, directional antennas, non-directional antennas, dipole antennas, folded dipole antennas, patch antennas, MIMO antennas, or the like. The communications antenna may be communicatively coupled to a radio component to transmit and/or receive signals, such as communications signals, to and/or from the user devices120(e.g.,122,124,126, or128).

Any of the user devices120(e.g.,122,124,126, or128) may include any suitable radio and/or transceiver for transmitting and/or receiving radio frequency (RF) signals in the bandwidth and/or channels corresponding to the communications protocols utilized by any of the user device(s)120to communicate with each other. The radio components may include hardware and/or software to modulate and/or demodulate communications signals according to pre-established transmission protocols. The radio components may further have hardware and/or software instructions to communicate via one or more Bluetooth, Wi-Fi, and/or Wi-Fi Direct protocols, as standardized by the Bluetooth and the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards.

In certain example embodiments, the radio component, in cooperation with the communications antennas, may be configured to communicate via 2.4 GHz channels (e.g., 802.11b, 802.11g, 802.11n, 802.11ax), 5 GHz channels (e.g., 802.11n, 802.11ac, 802.11ax), or 60 GHZ channels (e.g., 802.11ad). In some embodiments, non-Wi-Fi protocols may be used for communications between devices, such as Bluetooth, dedicated short-range communication (DSRC), Ultra-High Frequency (UHF) (e.g., IEEE 802.11af, IEEE 802.22), white band frequency (e.g., white spaces), or other packetized radio communications. The radio component may include any known receiver and baseband suitable for communicating via the communications protocols. The radio component may further include a low noise amplifier (LNA), additional signal amplifiers, an analog-to-digital (A/D) converter, one or more buffers, and digital baseband.

Some embodiments may be used in conjunction with devices and/or networks operating in accordance with existing. Wireless Fidelity (Wi-Fi) Alliance (WFA) Specifications, including Wi-Fi Neighbor Awareness Networking (NAN) Technical Specification (e.g., NAN and NAN2) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing WFA Peer-to-Peer (P2P) specifications and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing Wireless-Gigabit-Alliance (WGA) specifications (Wireless Gigabit Alliance, Inc WiGig MAC and PHY Specification) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing IEEE 802.11 standards and/or amendments (e.g., 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ax, 802.11ad, 802.1lay, 802.11az, etc.).

FIG. 2depicts an illustrative schematic diagram for detecting attacks on frequency offset, in accordance with one or more example embodiments of the present disclosure.

A Bluetooth® feature for performing distance measurements between two devices that are configured for Bluetooth® transmissions is known as High Accuracy Distance Measurement (HADM). The two devices may be known as an initiator device and a reflector device. The two devices may be any of user device(s)120(e.g.,122,124,126, and128) as depicted inFIG. 1. These distance measurements may be conducted through packet and tone signal exchanges between the initiator device and the reflector device, which may also be known as steps.

The current mechanism for calculating a distance between the initiator device and the reflector device uses a phase change of the tone signal propagated through the air from the reflector device to the initiator device. The phase change of the tone signal may be calculated as:

where f represents a frequency of the tone signal, t represents the time of propagation, D represents the distance of propagation, and C represents the speed of light. Thus, the distance between the initiator device and the reflector device, which is represented by D, is directly correlated to the phase change of the tone signal.

In some instances, as depicted inFIG. 2, in order to avoid ambiguity in the phase change calculation associated with the circular nature of a phase and to allow for the measurement of increased distances, multiple frequencies may be used to determine multiple phase change measurements on multiple channels. Thus, during the HADM frequency offset estimation step200, a first HADM phase estimation step202may be carried out at Channel 1, a second HADM phase estimation step204may be carried out at Channel 2, and a third HADM phase estimation step206may be carried out at Channel 3. The first HADM phase estimation step202, the second HADM phase estimation step204, and the third HADM phase estimation step206may occur at the initiator device when a tone signal has been transmitted to the initiator device from the reflector device. Each of Channels 1, 2, and 3 should reflect the same distance between the initiator device and the reflector device.

Because frequency offset may naturally occur in various instances, the frequency of the tone signal, f, may vary from the actual frequency of the tone signal. Frequency offset may thus affect the phase change formula such that the frequency used to calculate phase change is (f+Δf), which is the sum of the actual frequency of the tone signal and the frequency offset. However, when the phase change formula calculates phase change as

the distance calculation will be impacted as Δf increases.

Further, because tone signals may be vulnerable to attacks or interference, frequency offset estimations may be affected when a tone signal has been attacked or interfered with. Inaccurate frequency offset estimations may then result in inaccurate compensations to inaccurate distance calculations, thus causing the entire HADM event to become corrupted.

FIG. 3depicts an illustrative schematic diagram for detecting attacks on frequency offset, in accordance with one or more example embodiments of the present disclosure.

In a mechanism300for detecting attacks on frequency offset, an initiator device302may first synchronize to a reflector device304by transmitting a sync packet306comprising a preamble and an access code. After the reflector device304has detected the sync packet306, the reflector device304may then transmit a packet308comprising a low-energy structure having at least a preamble comprising an access code and a coded sequence of bits. The packet308may further include a trailer, and the packet308may obtain its security from a pseudo-random sequence of coded bits used in the access code. In some instances, the packet308may be a partial packet comprising only the preamble. After the reflector device304has transmitted the packet308, the reflector device304may then transmit a tone signal310to the initiator device302.

When the initiator device302receives the packet308, the initiator device302may detect the packet and calculate a first frequency offset estimation312of the coded sequence of bits. The packet308may be low-energy coded, which is a type of Gaussian Frequency Shift Keying (GFSK) coding. GFSK coding provides for each of the coded sequence of bits to be encoded into tones of various frequencies. The estimation of the first frequency offset estimation312of the packet308is particularly beneficial because of the increased accuracy associated with frequency offset estimations of a packet. Further, the coded sequence of bits of the packet308are encoded and are therefore unknown to the attacker, which renders the packet308less vulnerable to attacks or other forms of interference.

When the initiator device302subsequently receives the tone signal310, the initiator device302may calculate a second frequency offset estimation314of the tone signal. The initiator device302may then calculate a difference between the first frequency offset estimation312and the second frequency offset estimation314.

If the difference is within an allowable threshold range, then the initiator device302may assume that no interference occurred during the transmission of the tone signal310. In such an instance, the initiator device302may proceed with the rest of the HADM event.

If the difference is not within an allowable threshold range, then the initiator device302may assume that interference has occurred during the transmission of the tone signal310. For example, attack signal316may be used to interfere with the tone signal310. Interference may take the form of unintentional interference, such as Wi-Fi signals in the surrounding area, another Bluetooth®-configured device in the surrounding area, or other energy sources operating in a similar frequency range, or a deliberate attack, such as a deliberate transmission of a stronger tone that has a deliberate frequency offset when compared to the tone signal310. For example, a hacker may opt to transmit an additional tone, an additional collection of tones, a whiteout signal, or other interference to disrupt the tone signal310. In another example, the unintentional interference may take the form of other energy sources operating in approximately the 2.4 GHz to 2.480 GHz frequency range. In such an instance, any distance calculations based on the tone signal310may be inaccurate, and thus the initiator device302may terminate future transmissions associated with the HADM event or flag the HADM event as invalid.

The allowable threshold range may vary. In some instances, the allowable threshold range may include a range of 10 kHz from the first frequency offset estimation312.

FIG. 4illustrates a flow diagram of illustrative process400for a mechanism for detecting attacks on frequency offset in a wireless network, in accordance with one or more example embodiments of the present disclosure.

At block402, a device (e.g., the user device(s)120and/or the AP102ofFIG. 1) may receive a packet from a reflector device, wherein the packet comprises an access code and a coded sequence of bits. The device may be an initiator device. The initiator device may be configured for Bluetooth® transmissions. The reflector device may also be configured for Bluetooth® transmissions.

At block404, the device may receive a tone signal from the reflector device.

At block406, the device may calculate a first frequency offset estimation associated with the packet. The packet may be coded using Gaussian Frequency Shift Keying (GFSK).

At block408, the device may calculate a second frequency offset estimation associated with the tone signal.

At block410, the device may calculate a difference between the first frequency offset estimation and the second frequency offset estimation.

At block412, the device may identify an allowable threshold range of the difference. If the device determines that the difference is not within the allowable threshold range, the device may further flag the tone signal as having been interfered with. An example of the tone signal being interfered with may include a transmission of an attack tone that is stronger than the tone signal. If the tone signal is flagged as having been interfered with, the device may further omit a subsequent frequency offset calculation. Alternatively, if the device determines that the difference is within the allowable threshold range, the device may further flag the tone signal as not having been interfered with. A distance between the initiator device and the reflector device may also be calculated based at least in part on the difference.

FIG. 5shows a functional diagram of an exemplary communication station500, in accordance with one or more example embodiments of the present disclosure. In one embodiment,FIG. 5illustrates a functional block diagram of a communication station that may be suitable for use as an AP102(FIG. 1) or a user device120(FIG. 1) in accordance with some embodiments. The communication station500may also be suitable for use as a handheld device, a mobile device, a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a wearable computer device, a femtocell, a high data rate (HDR) subscriber station, an access point, an access terminal, or other personal communication system (PCS) device.

The communication station500may include communications circuitry502and a transceiver510for transmitting and receiving signals to and from other communication stations using one or more antennas501. The communications circuitry502may include circuitry that can operate the physical layer (PHY) communications and/or medium access control (MAC) communications for controlling access to the wireless medium, and/or any other communications layers for transmitting and receiving signals. The communication station500may also include processing circuitry506and memory508arranged to perform the operations described herein. In some embodiments, the communications circuitry502and the processing circuitry506may be configured to perform operations detailed in the above figures, diagrams, and flows.

In accordance with some embodiments, the communications circuitry502may be arranged to contend for a wireless medium and configure frames or packets for communicating over the wireless medium. The communications circuitry502may be arranged to transmit and receive signals. The communications circuitry502may also include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the processing circuitry506of the communication station500may include one or more processors. In other embodiments, two or more antennas501may be coupled to the communications circuitry502arranged for sending and receiving signals. The memory508may store information for configuring the processing circuitry506to perform operations for configuring and transmitting message frames and performing the various operations described herein. The memory508may include any type of memory, including non-transitory memory, for storing information in a form readable by a machine (e.g., a computer). For example, the memory508may include a computer-readable storage device, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices and other storage devices and media.

The machine (e.g., computer system)600may include a hardware processor602(e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory604and a static memory606, some or all of which may communicate with each other via an interlink (e.g., bus)608. The machine600may further include a power management device632, a graphics display device610, an alphanumeric input device612(e.g., a keyboard), and a user interface (UI) navigation device614(e.g., a mouse). In an example, the graphics display device610, alphanumeric input device612, and UI navigation device614may be a touch screen display. The machine600may additionally include a storage device (i.e., drive unit)616, a signal generation device618(e.g., a speaker), an attack on frequency offset detection device619, a network interface device/transceiver620coupled to antenna(s)630, and one or more sensors628, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensor. The machine600may include an output controller634, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.)). The operations in accordance with one or more example embodiments of the present disclosure may be carried out by a baseband processor. The baseband processor may be configured to generate corresponding baseband signals. The baseband processor may further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with the hardware processor602for generation and processing of the baseband signals and for controlling operations of the main memory604, the storage device616, and/or the attack on frequency offset detection device619. The baseband processor may be provided on a single radio card, a single chip, or an integrated circuit (IC).

The attack on frequency offset detection device619may carry out or perform any of the operations and processes (e.g., process400) described and shown above.

It is understood that the above are only a subset of what the attack on frequency offset detection device619may be configured to perform and that other functions included throughout this disclosure may also be performed by the attack on frequency offset detection device619.

FIG. 7is a block diagram of a radio architecture105A,105B in accordance with some embodiments that may be implemented in any one of the example APs102and/or the example user device(s)120ofFIG. 1. Radio architecture105A,105B may include radio front-end module (FEM) circuitry704a-b, radio IC circuitry706a-band baseband processing circuitry708a-b. Radio architecture105A,105B as shown includes both Wireless Local Area Network (WLAN) functionality and Bluetooth (BT) functionality although embodiments are not so limited. In this disclosure, “WLAN” and “Wi-Fi” are used interchangeably.

FEM circuitry704a-bmay include a WLAN or Wi-Fi FEM circuitry704aand a Bluetooth (BT) FEM circuitry704b. The WLAN FEM circuitry704amay include a receive signal path comprising circuitry configured to operate on WLAN RF signals received from one or more antennas701, to amplify the received signals and to provide the amplified versions of the received signals to the WLAN radio IC circuitry706afor further processing. The BT FEM circuitry704bmay include a receive signal path which may include circuitry configured to operate on BT RF signals received from one or more antennas701, to amplify the received signals and to provide the amplified versions of the received signals to the BT radio IC circuitry706bfor further processing. FEM circuitry704amay also include a transmit signal path which may include circuitry configured to amplify WLAN signals provided by the radio IC circuitry706afor wireless transmission by one or more of the antennas701. In addition, FEM circuitry704bmay also include a transmit signal path which may include circuitry configured to amplify BT signals provided by the radio IC circuitry706bfor wireless transmission by the one or more antennas. In the embodiment ofFIG. 7, although FEM704aand FEM704bare shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of an FEM (not shown) that includes a transmit path and/or a receive path for both WLAN and BT signals, or the use of one or more FEM circuitries where at least some of the FEM circuitries share transmit and/or receive signal paths for both WLAN and BT signals.

Baseband processing circuity708a-bmay include a WLAN baseband processing circuitry708aand a BT baseband processing circuitry708b. The WLAN baseband processing circuitry708amay include a memory, such as, for example, a set of RAM arrays in a Fast Fourier Transform or Inverse Fast Fourier Transform block (not shown) of the WLAN baseband processing circuitry708a. Each of the WLAN baseband circuitry708aand the BT baseband circuitry708bmay further include one or more processors and control logic to process the signals received from the corresponding WLAN or BT receive signal path of the radio IC circuitry706a-b, and to also generate corresponding WLAN or BT baseband signals for the transmit signal path of the radio IC circuitry706a-b. Each of the baseband processing circuitries708aand708bmay further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with a device for generation and processing of the baseband signals and for controlling operations of the radio IC circuitry706a-b.

Referring still toFIG. 7, according to the shown embodiment, WLAN-BT coexistence circuitry713may include logic providing an interface between the WLAN baseband circuitry708aand the BT baseband circuitry708bto enable use cases requiring WLAN and BT coexistence. In addition, a switch703may be provided between the WLAN FEM circuitry704aand the BT FEM circuitry704bto allow switching between the WLAN and BT radios according to application needs. In addition, although the antennas701are depicted as being respectively connected to the WLAN FEM circuitry704aand the BT FEM circuitry704b, embodiments include within their scope the sharing of one or more antennas as between the WLAN and BT FEMs, or the provision of more than one antenna connected to each of FEM704aor704b.

In some embodiments, the front-end module circuitry704a-b, the radio IC circuitry706a-b, and baseband processing circuitry708a-bmay be provided on a single radio card, such as wireless radio card702. In some other embodiments, the one or more antennas701, the FEM circuitry704a-band the radio IC circuitry706a-bmay be provided on a single radio card. In some other embodiments, the radio IC circuitry706a-band the baseband processing circuitry708a-bmay be provided on a single chip or integrated circuit (IC), such as IC712.

In some embodiments, the radio architecture105A,105B may be configured for high-efficiency Wi-Fi (HEW) communications in accordance with the IEEE 802.11ax standard. In these embodiments, the radio architecture105A,105B may be configured to communicate in accordance with an OFDMA technique, although the scope of the embodiments is not limited in this respect.

In some embodiments, as further shown inFIG. 7, the BT baseband circuitry708bmay be compliant with a Bluetooth (BT) connectivity standard such as Bluetooth, Bluetooth 8.0 or Bluetooth 6.0, or any other iteration of the Bluetooth Standard.

In some embodiments, the radio architecture105A,105B may include other radio cards, such as a cellular radio card configured for cellular (e.g., SGPP such as LTE, LTE-Advanced or 7G communications).

In some IEEE 802.11 embodiments, the radio architecture105A,105B may be configured for communication over various channel bandwidths including bandwidths having center frequencies of about 900 MHz, 2.4 GHz, 5 GHz, and bandwidths of about 2 MHz, 4 MHz, 5 MHz, 5.5 MHz, 6 MHz, 8 MHz, 10 MHz, 20 MHz, 40 MHz, 80 MHz (with contiguous bandwidths) or 80+80 MHz (160 MHz) (with non-contiguous bandwidths). In some embodiments, a 920 MHz channel bandwidth may be used. The scope of the embodiments is not limited with respect to the above center frequencies however.

FIG. 8illustrates WLAN FEM circuitry704ain accordance with some embodiments. Although the example ofFIG. 8is described in conjunction with the WLAN FEM circuitry704a, the example ofFIG. 8may be described in conjunction with the example BT FEM circuitry704b(FIG. 7), although other circuitry configurations may also be suitable.

In some embodiments, the FEM circuitry704amay include a TX/RX switch802to switch between transmit mode and receive mode operation. The FEM circuitry704amay include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry704amay include a low-noise amplifier (LNA)806to amplify received RF signals803and provide the amplified received RF signals807as an output (e.g., to the radio IC circuitry706a-b(FIG. 7). The transmit signal path of the circuitry704amay include a power amplifier (PA) to amplify input RF signals809(e.g., provided by the radio IC circuitry706a-b), and one or more filters812, such as band-pass filters (BPFs), low-pass filters (LPFs) or other types of filters, to generate RF signals815for subsequent transmission (e.g., by one or more of the antennas701(FIG. 7) via an example duplexer814.

In some dual-mode embodiments for Wi-Fi communication, the FEM circuitry704amay be configured to operate in either the 2.4 GHz frequency spectrum or the 5 GHz frequency spectrum. In these embodiments, the receive signal path of the FEM circuitry704amay include a receive signal path duplexer804to separate the signals from each spectrum as well as provide a separate LNA806for each spectrum as shown. In these embodiments, the transmit signal path of the FEM circuitry704amay also include a power amplifier810and a filter812, such as a BPF, an LPF or another type of filter for each frequency spectrum and a transmit signal path duplexer804to provide the signals of one of the different spectrums onto a single transmit path for subsequent transmission by the one or more of the antennas701(FIG. 7). In some embodiments, BT communications may utilize the 2.4 GHz signal paths and may utilize the same FEM circuitry704aas the one used for WLAN communications.

FIG. 9illustrates radio IC circuitry706ain accordance with some embodiments. The radio IC circuitry706ais one example of circuitry that may be suitable for use as the WLAN or BT radio IC circuitry706a/706b(FIG. 7), although other circuitry configurations may also be suitable. Alternatively, the example ofFIG. 9may be described in conjunction with the example BT radio IC circuitry706b.

In some embodiments, the radio IC circuitry706amay include a receive signal path and a transmit signal path. The receive signal path of the radio IC circuitry706amay include at least mixer circuitry902, such as, for example, down-conversion mixer circuitry, amplifier circuitry906and filter circuitry908. The transmit signal path of the radio IC circuitry706amay include at least filter circuitry912and mixer circuitry914, such as, for example, up-conversion mixer circuitry. Radio IC circuitry706amay also include synthesizer circuitry904for synthesizing a frequency905for use by the mixer circuitry902and the mixer circuitry914. The mixer circuitry902and/or914may each, according to some embodiments, be configured to provide direct conversion functionality. The latter type of circuitry presents a much simpler architecture as compared with standard super-heterodyne mixer circuitries, and any flicker noise brought about by the same may be alleviated for example through the use of OFDM modulation.FIG. 9illustrates only a simplified version of a radio IC circuitry, and may include, although not shown, embodiments where each of the depicted circuitries may include more than one component. For instance, mixer circuitry914may each include one or more mixers, and filter circuitries908and/or912may each include one or more filters, such as one or more BPFs and/or LPFs according to application needs. For example, when mixer circuitries are of the direct-conversion type, they may each include two or more mixers.

In some embodiments, mixer circuitry902may be configured to down-convert RF signals807received from the FEM circuitry704a-b(FIG. 7) based on the synthesized frequency905provided by synthesizer circuitry904. The amplifier circuitry906may be configured to amplify the down-converted signals and the filter circuitry908may include an LPF configured to remove unwanted signals from the down-converted signals to generate output baseband signals907. Output baseband signals907may be provided to the baseband processing circuitry708a-b(FIG. 7) for further processing. In some embodiments, the output baseband signals907may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry902may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry914may be configured to up-convert input baseband signals911based on the synthesized frequency905provided by the synthesizer circuitry904to generate RF output signals809for the FEM circuitry704a-b. The baseband signals911may be provided by the baseband processing circuitry708a-band may be filtered by filter circuitry912. The filter circuitry912may include an LPF or a BPF, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry902and the mixer circuitry914may each include two or more mixers and may be arranged for quadrature down-conversion and/or up-conversion respectively with the help of synthesizer904. In some embodiments, the mixer circuitry902and the mixer circuitry914may each include two or more mixers each configured for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry902and the mixer circuitry914may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuitry902and the mixer circuitry914may be configured for super-heterodyne operation, although this is not a requirement.

Mixer circuitry902may comprise, according to one embodiment: quadrature passive mixers (e.g., for the in-phase (I) and quadrature phase (Q) paths). In such an embodiment, RF input signal807fromFIG. 9may be down-converted to provide I and Q baseband output signals to be sent to the baseband processor.

In some embodiments, the LO signals may differ in duty cycle (the percentage of one period in which the LO signal is high) and/or offset (the difference between start points of the period). In some embodiments, the LO signals may have an 85% duty cycle and an 80% offset. In some embodiments, each branch of the mixer circuitry (e.g., the in-phase (I) and quadrature phase (Q) path) may operate at an 80% duty cycle, which may result in a significant reduction is power consumption.

The RF input signal807(FIG. 8) may comprise a balanced signal, although the scope of the embodiments is not limited in this respect. The I and Q baseband output signals may be provided to low-noise amplifier, such as amplifier circuitry906(FIG. 9) or to filter circuitry908(FIG. 9).

In some embodiments, the output baseband signals907and the input baseband signals911may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals907and the input baseband signals911may be digital baseband signals. In these alternate embodiments, the radio IC circuitry may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry.

In some embodiments, the synthesizer circuitry904may be a fractional-N synthesizer or a fractional N/N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry904may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. According to some embodiments, the synthesizer circuitry904may include digital synthesizer circuitry. An advantage of using a digital synthesizer circuitry is that, although it may still include some analog components, its footprint may be scaled down much more than the footprint of an analog synthesizer circuitry. In some embodiments, frequency input into synthesizer circuity904may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. A divider control input may further be provided by either the baseband processing circuitry708a-b(FIG. 7) depending on the desired output frequency905. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table (e.g., within a Wi-Fi card) based on a channel number and a channel center frequency as determined or indicated by the example application processor710. The application processor710may include, or otherwise be connected to, one of the example secure signal converter101or the example received signal converter103(e.g., depending on which device the example radio architecture is implemented in).

In some embodiments, synthesizer circuitry904may be configured to generate a carrier frequency as the output frequency905, while in other embodiments, the output frequency905may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the output frequency905may be a LO frequency (fLO).

FIG. 10illustrates a functional block diagram of baseband processing circuitry708ain accordance with some embodiments. The baseband processing circuitry708ais one example of circuitry that may be suitable for use as the baseband processing circuitry708a(FIG. 7), although other circuitry configurations may also be suitable. Alternatively, the example ofFIG. 9may be used to implement the example BT baseband processing circuitry708bofFIG. 7.

The baseband processing circuitry708amay include a receive baseband processor (RX BBP)1002for processing receive baseband signals909provided by the radio IC circuitry706a-b(FIG. 7) and a transmit baseband processor (TX BBP)1004for generating transmit baseband signals911for the radio IC circuitry706a-b. The baseband processing circuitry708amay also include control logic1006for coordinating the operations of the baseband processing circuitry708a.

In some embodiments (e.g., when analog baseband signals are exchanged between the baseband processing circuitry708a-band the radio IC circuitry706a-b), the baseband processing circuitry708amay include ADC1010to convert analog baseband signals1009received from the radio IC circuitry706a-bto digital baseband signals for processing by the RX BBP1002. In these embodiments, the baseband processing circuitry708amay also include DAC1012to convert digital baseband signals from the TX BBP1004to analog baseband signals1011.

The term “access point” (AP) as used herein may be a fixed station. An access point may also be referred to as an access node, a base station, an evolved node B (eNodeB), or some other similar terminology known in the art. An access terminal may also be called a mobile station, user equipment (UE), a wireless communication device, or some other similar terminology known in the art. Embodiments disclosed herein generally pertain to wireless networks. Some embodiments may relate to wireless networks that operate in accordance with one of the IEEE 802.11 standards.

The following examples pertain to further embodiments.

Example 1 may include a device comprising processing circuitry coupled to storage, the processing circuitry configured to: receive a packet from a reflector device, wherein the packet comprises an access code and a coded sequence of bits; receive a tone signal from the reflector device; calculate a first frequency offset estimation associated with the packet; calculate a second frequency offset estimation associated with the tone signal; calculate a difference between the first frequency offset estimation and the second frequency offset estimation; and identify an allowable threshold range of the difference.

Example 2 may include the device of example 1 and/or some other example herein, wherein the processing circuitry is further configured to: determine that the difference is not within the allowable threshold range; and flag the tone signal as having been interfered with.

Example 3 may include the device of example 2 and/or some other example herein, wherein the processing circuitry is further configured to: omit a subsequent frequency offset calculation.

Example 4 may include the device of example 2 and/or some other example herein, wherein interference with the tone signal comprises a transmission of an attack tone that is stronger than the tone signal.

Example 5 may include the device of example 4 and/or some other example herein, wherein the processing circuitry is further configured to: determine that the difference is within the allowable threshold range; and flag the tone signal as not having been interfered with.

Example 6 may include the device of example 1 and/or some other example herein, wherein the device is an initiator device, and the reflector device and the initiator device are configured for Bluetooth® transmissions.

Example 7 may include the device of example 1 and/or some other example herein, wherein the packet is coded using Gaussian Frequency Shift Keying (GFSK).

Example 8 may include the device of example 1 and/or some other example herein, wherein a distance between the device and the reflector device is calculated based at least in part on the difference.

Example 9 may include the device of example 1 and/or some other example herein, further comprising a transceiver configured to transmit and receive wireless signals.

Example 10 may include the device of example 9 and/or some other example herein, further comprising an antenna coupled to the transceiver to cause to send the packet and the tone signal.

Example 11 may include a non-transitory computer-readable medium storing computer-executable instructions which when executed by one or more processors result in performing operations comprising: receiving a packet from a reflector device, wherein the packet comprises an access code and a coded sequence of bits; receiving a tone signal from the reflector device; calculating a first frequency offset estimation associated with the packet; calculating a second frequency offset estimation associated with the tone signal; calculating a difference between the first frequency offset estimation and the second frequency offset estimation; and identifying an allowable threshold range of the difference.

Example 12 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the computer-executable instructions further result in operations comprising: determine that the difference is not within the allowable threshold range; and flag the tone signal as having been interfered with.

Example 13 may include the non-transitory computer-readable medium of example 12 and/or some other example herein, wherein the computer-executable instructions further result in operations comprising: omitting a subsequent frequency offset calculation.

Example 14 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the computer-executable instructions further result in operations comprising: determine that the difference is within the allowable threshold range; and flag the tone signal as not having been interfered with.

Example 15 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the reflector device is configured for Bluetooth® transmissions.

Example 16 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the packet is coded using Gaussian Frequency Shift Keying (GFSK).

Example 17 may include a method comprising: receiving, at an initiator device, a packet from a reflector device, wherein the packet comprises an access code and a coded sequence of bits; receiving, at the initiator device, a tone signal from the reflector device; calculating a first frequency offset estimation associated with the packet; calculating a second frequency offset estimation associated with the tone signal; calculating a difference between the first frequency offset estimation and the second frequency offset estimation; and identifying an allowable threshold range of the difference.

Example 18 may include the method of example 17 and/or some other example herein, further comprising: determining that the difference is not within the allowable threshold range; and flagging the tone signal as having been interfered with.

Example 19 may include the method of example 18 and/or some other example herein, further comprising: omitting a subsequent frequency offset calculation.

Example 20 may include the method of example 17 and/or some other example herein, further comprising: determining that the difference is within the allowable threshold range; and flagging the tone signal as not having been interfered with.

Example 22 may include an apparatus comprising logic, modules, and/or circuitry to perform one or more elements of a method described in or related to any of examples 1-20, or any other method or process described herein.

Example 23 may include a method, technique, or process as described in or related to any of examples 1-20, or portions or parts thereof.

Example 25 may include a method of communicating in a wireless network as shown and described herein.

Example 26 may include a system for providing wireless communication as shown and described herein.

Example 27 may include a device for providing wireless communication as shown and described herein.