Guided placement of wireless devices for optimal performance

Abstract

Described herein are techniques for guided placement of wireless devices. In one exemplary embodiment, a Wi-Fi wireless device includes a radio frequency (RF) transceiver connected to a baseband processor. The RF transceiver is configured to receive an RF signal transmitted over a wireless channel and convert the RF signal into a modulated digital signal. The baseband processor is configured to receive the modulated digital signal from the RF transceiver, extract a wireless packet from the modulated digital signal, and calculate an Exponential Effective SNR Mapping (EESM) value indicative of the quality of the wireless channel at a current location of the wireless device based on a preamble of the wireless packet. The baseband processor is further configured to provide a quality indication based on the EESM value for the current location of the wireless device.

Description

[Technical field]

[0001] This application is an international application of U.S. Non-provisional Application No. 16 / 360,218, filed March 19, 2019, and claims priority to and the benefit of U.S. Provisional Application No. 62 / 798,342, filed January 29, 2019, all of which are incorporated herein by reference in their entireties.

[0002] This disclosure relates to wireless communication via the IEEE 802.11 protocol. [Background technology]

[0003] The IEEE 802.11 (wi-fi) standard has been developed to provide high throughput wireless local area networks (WLANs). Typically, wireless devices are configured to provide some visual indication (e.g., a visual icon on a screen) of the strength of the signal received over a particular WLAN's radio channel. For example, the signal strength indication can be based on a Received Signal Strength Indicator (RSSI) metric that measures the power of the signal coming to the wireless device. However, RSSI-based indications can be misleading about the actual quality of the wireless channel because the RSSI metric is based on an evaluation of an analog radio frequency (RF) signal, and can mask deep fades in the channel that may include signal interference and cause transmission errors. Thus, such RSSI-based indications are not completely reliable in predicting and reflecting the quality (e.g., throughput) of the wireless channel leading to the wireless device. [Brief description of the drawings]

[0004] [Figure 1] 1 illustrates an example of an operational context of the described technique for guided placement of a wireless device, according to some embodiments. [Diagram 2]1 is a diagram of a simulation example of two signal realizations of the same wireless channel model. [Figure 3A] 2 illustrates a Protocol Data Unit (PPDU) wireless packet structure that can be used for guided placement of a wireless device in some embodiments. [Figure 3B] FIG. 2 illustrates the structure of a Null Data Packet (NPD) wireless packet that can be used for guided placement of a wireless device in some embodiments. [Figure 4] 1 is a schematic diagram illustrating quality indication logic for guided placement of a wireless device according to an exemplary embodiment. [Diagram 5] 4 is a flow diagram of a method for guided positioning of a wireless device according to an example embodiment. [Figure 6] 1 is a schematic diagram illustrating an example wireless device according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] In the following description, numerous specific details are set forth, such as examples of specific systems, components, methods, and the like, to provide a better understanding of different embodiments of the described techniques for guided placement of wireless devices for optimal wireless channel performance. However, it will be apparent to one of ordinary skill in the art that at least some embodiments may be practiced without these specific details. In other instances, well-known components, elements, or methods have not been described in detail or have been shown in simplified block diagram form to avoid unnecessarily obscuring what is described herein. Thus, the specific details set forth below are merely exemplary. A particular implementation may vary from these example details and still be considered to be within the spirit and scope of the present invention.

[0006] When the description herein refers to "an embodiment," "one embodiment," "an exemplary embodiment," "some embodiments," and "different embodiments," this means that a particular feature, structure, step, operation, or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. Furthermore, although the phrases "an embodiment," "one embodiment," "an exemplary embodiment," "some embodiments," and "different embodiments" appear in various places in the description herein, they are not necessarily all referring to the same embodiment.

[0007] The description herein includes references to the accompanying drawings, which form a part of the detailed description. In these drawings, a description is given according to exemplary embodiments. These embodiments, which may also be referred to herein as "examples," are described in sufficient detail to enable one of ordinary skill in the art to practice embodiments of the claimed subject matter described herein. These embodiments may be combined, alternative embodiments may be utilized, or structural, logical, and electrical changes may be made without departing from the scope and spirit of the claimed subject matter. It should be understood that the embodiments described herein are not intended to limit the scope of the subject matter, but rather to enable one of ordinary skill in the art to practice, make, and / or use the subject matter.

[0008] Described herein are different embodiments of techniques for guided placement of wireless devices for optimal wireless channel performance. Examples of such wireless devices include, but are not limited to, personal computers (e.g., laptop computers, notebook computers, etc.), mobile computing devices (e.g., tablets, tablet computers, e-reader devices, etc.), mobile communication devices configured for wi-fi operation (e.g., smartphones, mobile phones, personal digital assistants, messaging devices, pocket PCs, etc.), wi-fi enabled audio / video / data recording and / or playback devices (e.g., cameras, voice recorders, handheld scanners, monitors, etc.), printed circuit board (PCB) modules configured for wi-fi operation, System-on-Chip (SoC) wi-fi semiconductor devices and multi-chip semiconductor packages, and other similar electronic or chip-level devices that can use wi-fi protocols and interfaces for communication.

[0009] As used herein, a "wireless" ("wi-fi") packet, channel, protocol, interface, device, or system refers to a packet, channel, protocol, interface, device, or system that complies with one or more IEEE 802.11 standards, such as, for example, IEEE 802.11 a / g / n / ac / p / ax or later standards. (Note that a wireless device or system may be a combo device that complies with one or more IEEE 802.11 standards as well as another standard, such as Bluetooth.) The IEEE 802.11 wireless standard is being developed to provide high throughput wireless local area networks (WLANs), such as, for example, high throughput (HT) and very high throughput (VHT) WLANs. For example, in an HT WLAN, a wireless device (also referred to as a "station," or STA) can associate with an access point device (also referred to as an AP), such as a wireless router, that operates on a 40 MHz radio channel. In a VHT WLAN, a wireless device can associate with an AP that operates on an 80 MHz radio channel. A wireless channel is a frequency range or band established for communication between an AP and a STA. During transmission, the wireless channel can be divided into multiple subcarrier bands (subcarriers) of several 100 kHz (e.g., 300 kHz) each, and transmission data can be multiplexed onto the subcarriers, for example, using orthogonal frequency division multiplexing (OFDM).

[0010] The quality of a wireless channel is typically indicated by its throughput (e.g., the amount of data in bits per second successfully received over the wireless channel), although other channel characteristics such as latency can also be used. The throughput of a wireless device can be highly dependent on its location. As used herein, "location" refers to the physical location and / or physical orientation of the wireless device. Moving a wireless device by just a few inches can significantly increase the throughput (and therefore the quality) of a wireless channel. However, users typically receive no guidance on where to place their wireless devices for better throughput.

[0011] Conventional approaches for placement guidance are based on a common RSSI metric. However, the RSSI metric only measures the power of the incoming analog RF signal and does not distinguish between the useful signal and interference that may be caused by other nearby devices, which may be significant in the unlicensed 2.4 GHz and 5 GHz bands. Furthermore, the RSSI metric tends to mask any deep fades that may be present in some, but not all, of the subcarriers of the wireless channel. Thus, although a wireless device can provide an RSSI-based visual indication of the strength of the received RF signal, such an indication may be misleading about the expected throughput (and therefore quality) of the wireless channel. For example, a large RSSI metric may be misleading when nearby interference dominates the RF signal of interest. Furthermore, a large RSSI metric may mask deep fades in the wireless channel that may cause transmission errors and thus reduce channel throughput.

[0012] To address these and other issues regarding placement guidance for wireless devices, the techniques described herein provide for using the Exponential Effective SNR Mapping (EESM) metric to predict the quality (e.g., throughput) of a wireless channel to a wireless device. EESM is an advanced metric that quantifies the quality of a wireless channel. The EESM metric is based on the signal strength of each subcarrier of the wireless channel and exponentially weights the signal-to-noise ratio (SNR) of each subcarrier. In this way, the EESM metric takes into account the instantaneous characteristics (e.g., deep fades) of the wireless channel and reflects a metric value that more accurately represents the throughput and overall quality of the channel. Furthermore, by using the EESM metric as a predictor of channel quality, better placement guidance can be provided for wireless devices with directional, polarized and / or switched antennas. (A switched antenna device is a device with two or more antennas in one RF chain, such that the device can select / switch to an antenna that provides better transmission quality.) Wireless devices with such antennas are highly location-dependent when attempting to provide good wireless communication. This is because the physical location of a device and its orientation (eg, the angle of its antenna relative to the AP) can greatly increase the throughput of a wireless channel.

[0013] In an exemplary embodiment, the wireless device includes a radio frequency (RF) transceiver and a baseband processor coupled to the RF transceiver. The RF transceiver is configured to receive an RF signal transmitted over a wireless channel and convert the RF signal into a modulated digital signal. The baseband processor is configured to receive the modulated digital signal from the RF transceiver, extract a wireless packet from the modulated digital signal, and calculate an EESM value indicative of a quality of a wireless channel at a current location of the wireless device based on a preamble of the wireless packet. The baseband processor is further configured to provide a quality indication based on the EESM value for the current location of the wireless device. In some aspects of this embodiment, the wireless packet may be a null data packet (NDP) or a protocol data unit (PPDU). To calculate the EESM value, in one aspect, the baseband processor is further configured to reference a β parameter value in a lookup table that stores pre-calculated β parameter values ​​for a plurality of modulation-and-coding schemes (MCS). In some aspects, to calculate the EESM value, the baseband processor is configured to estimate a signal-to-noise ratio (SNR) value for the wireless channel and to use a signal strength value per subcarrier of the wireless channel. In an exemplary aspect, the baseband processor is configured to identify whether a wireless packet is valid (e.g., whether the wireless packet was sent specifically to the wireless device). In one aspect, the wireless device has a display and the quality indication is displayed on the display as a visual icon. In another aspect, the wireless device has a row of light emitting diodes (LEDs) and the quality indication is displayed on the row of LEDs. In some aspects, the baseband processor is further configured to periodically recalculate the EESM value.For example, the baseband processor may be configured to calculate a new EESM value and provide a new quality indication based on the new EESM value if the current location of the wireless device changes. In another embodiment, the baseband processor may be configured to calculate the new EESM value and the new quality indication based on a pre-configured time interval and / or a particular type of received wireless packet.

[0014] In another exemplary embodiment, a method of guided positioning of a wireless device for a wireless channel includes receiving, by the wireless device at a first location, over the wireless channel, a first wireless packet including a first preamble, calculating a first EESM value indicative of a first quality of the wireless channel at the first location based on the first preamble of the first wireless packet, providing a first quality indication based on the first EESM value for the first location of the wireless device, receiving, by the wireless device at a second location, different from the first location, over the wireless channel, a second wireless packet including a second preamble, calculating a second EESM value indicative of a second quality of the wireless channel at the second location based on the second preamble of the second wireless packet, and providing a second quality indication based on the second EESM value for the second location of the wireless device. In some aspects of this embodiment, one or both of the first wireless packet and the second wireless packet may be an NDP and / or PPDU. In an exemplary embodiment, the first EESM value calculation and the second EESM value calculation may reference one or more β parameters for one or more respective MCSs. In an embodiment, the first EESM value calculation estimates a first SNR value for the wireless channel, and the second EESM value calculation estimates a second SNR value for the wireless channel. In some embodiments, the first EESM value calculation and the second EESM value calculation further determine a signal strength value for each subcarrier of the wireless channel. In an exemplary embodiment, the method further determines whether the first wireless packet and / or the second wireless packet are valid (e.g., whether the wireless packet was sent specifically to the wireless device). In an embodiment, the first quality indication and the second quality indication provide a visual icon on a display of the wireless device. In another embodiment, the first quality indication and the second quality indication provide drive a string of LEDs on the wireless device.In some aspects, the above method may further include periodically calculating a current EESM value indicative of a current quality of a wireless channel at a current location of the wireless device, the period of calculation being based on a pre-set time interval and / or a particular type of received wireless packet.

[0015] In another exemplary embodiment, a method for locating a wireless device for a wireless channel includes receiving, at the wireless device, a wireless packet including training field data (e.g., NDP or PPDU); calculating, by the wireless device, an EESM value indicative of a quality of the wireless channel at a current location of the wireless device based on at least the training field data; and providing, by the wireless device, a quality / throughput indication based on the EESM value for the current location of the wireless device. In one aspect of this embodiment, the calculation of the EESM value includes referencing a plurality of β parameter values ​​for a plurality of respective modulation-and-coding schemes (MCSs), calculating a plurality of EESM values ​​based on the plurality of β parameter values, and selecting a maximum EESM value of the plurality of EESM values ​​as the EESM value for the quality of the wireless channel at the current location of the wireless device. In another aspect, the calculation of the EESM value includes deriving the EESM value based on an SNR value of the wireless channel and a signal strength of each subcarrier of the wireless channel, and based on the same symbols in the training field data, the SNR value of the wireless channel can be estimated and / or the signal strength of each subcarrier of the wireless channel can be determined. In one aspect of this embodiment, the method further includes determining whether the wireless packet is valid. In one aspect, providing the quality / throughput indication can display a visual icon on a display of the wireless device, while in another aspect, providing the quality / throughput indication can drive a string of LEDs. In one aspect of this embodiment, the method can further include periodically recalculating the EESM value, where the periodicity of the calculation can be based on a pre-set time interval and / or a particular type of wireless packet received.

[0016] FIG. 1 illustrates an example of an operational scenario of the technique for guided placement of wireless devices described herein. Wireless device (STA) 100 is configured to communicate with access point device (AP) 10 via a wireless channel. At location A (20), STA 100 calculates an EESM value indicative of throughput A (25) at that location according to the technique described herein. Based on the calculated EESM value, a quality indication is provided by STA 100 to turn on two (of six) of its LEDs. STA 100 is subsequently moved to location B (30). At location B (30), STA 100 calculates a new EESM value indicative of throughput B (35) at that location according to the technique described herein. Based on the new EESM value, a quality indication is provided by STA 100 to turn on all six of its LEDs. Based on this visual indication, a user of the wireless device 100 can easily determine that the throughput, and correspondingly the quality, of the wireless channel to the AP 10 is much better at location B (30) than at location A (20). In general, a higher EESM value for a particular location indicates a higher quality of the wireless channel than a location having a lower EESM value, and thus indicates that a higher throughput is achievable at that particular location. Thus, in FIG. 1, by moving the wireless device 100 from location A (20) to location B (30), the user can easily determine by looking at the row of LEDs that the throughput of the wireless device will be higher at location B than at location A. In this manner, the techniques described herein provide guided placement of the wireless device for optimal wireless channel performance.

[0017] It should be noted that the operational scenario illustrated in FIG. 1 is merely an example. In some embodiments, the change from position A to position B may include a change in the physical location of the device (e.g., a displacement of physical coordinates). In another embodiment, the change from position A to position B may only include a change in the orientation of the wireless device (e.g., a change in the angle of the wireless device's antenna relative to the access point device) without a change in physical location. In some embodiments, the wireless device can provide the quality indication as a visual icon on a display (e.g., if the wireless device has a display). In another embodiment, the wireless device can provide the calculated EESM value and / or the quality indication to a smartphone or tablet (e.g., if the wireless device is a stationary device that does not have and / or is not suitable for providing a visual indication (such as a security camera or printer, etc.). The operational scenario of FIG. 1 should therefore be considered in an illustrative sense, rather than a restrictive sense.

[0018] In some embodiments, the techniques described herein calculate new EESM values ​​at each new position of the wireless device, provide new quality indications, and provide new visual indications based thereon. Alternatively or additionally, in some embodiments, the EESM values ​​can be calculated periodically, and the quality indications based thereon can be continuously shown to the user. In various embodiments, the use of the EESM metric values ​​in such a manner can depend on the specific characteristics of the wireless device (such as the form factor of the wireless device, the specific usage situation, and the environment (such as the presence or absence of obstructions in the channel path, for example)). In some embodiments, the calculated EESM values ​​and / or the quality indications based thereon can be exported to end user devices (such as, for example, smartphones, tablets, laptop / notebook computers, etc.) via an application programing interface (API) to provide maximum flexibility of use. In various embodiments, the visual indications provided to the user can be different wi-fi signal icons or wi-fi bar icons (for example, for wireless devices with a touch screen), or another type of visual indication (for example, one or more LEDs that change color) for wireless devices that do not have a display.

[0019] Traditionally, EESM metrics are used in cellular communications to predict packet error rate (PER) for link rate adaptation schemes. Unlike such traditional schemes that use EESM to predict PER, the techniques described herein use EESM metrics for a different purpose (to guide the selection of a better location for a wireless device). Furthermore, unlike traditional solutions that use RSSI metrics to indicate the strength of a received analog RF signal, the techniques described herein calculate and use EESM metrics to provide a visual indication of the quality of the wireless channel configured for a wireless device. The difference between using RSSI and using EESM metrics to predict channel performance is illustrated in FIG. 2.

[0020] In Fig. 2, a simulation example of two signal realizations (signals H1 and H2) in two wireless channels with the same channel model is plotted for each subchannel versus subchannel (along the x-axis) and signal strength (along the y-axis). Line graphs 201 and 202 show the average power of each of the signals H1 and H2 across the subcarriers of the two respective wireless channels. Signal H1 has an average power strength of -28.2173 dB, whereas signal H2 has an average power strength of -26.7107 dB. Line 202 shows that signal H2 has a higher average power than signal H1, so the RSSI value of signal H2 may be higher than the RSSI value of signal H1. However, line 202 shows a deep fade 202a (an example of a frequency-selective channel characteristic) that may cause wireless packets transmitted on the channel of signal H2 to fail. Thus, even though signal H2 is approximately 2 dB higher in average power, its wireless channel will be considered to have a lower throughput than the channel of signal H1 because the bits transmitted on the subcarrier will be lost in the deep fade 202a. Note that the EESM metric does not have this problem if used in accordance with the techniques described herein because the techniques take into account the quality of the wireless channel across all its subchannels. Thus, signal H1 will have a better EESM metric than signal H2, and therefore signal H1's channel will be considered to have a better quality (e.g., throughput) than signal H2's channel.

[0021] In accordance with the techniques described herein, the EESM metric values ​​are calculated according to the following equations (1) and (2):

number

[0022] According to formula (1), γ with respect to β i The ratios of are summed exponentially and the sum is averaged over N subcarriers. eff EESM reflects a non-linear scale of the average power across subcarriers for a particular symbol in a received packet. Calculated in this way, the EESM value takes into account the SNR of a particular symbol across the entire channel, but removes the effects of any external signal interference and fades in the wireless channel. Furthermore, the β parameter has an MCS dependency, which allows fine tuning of the EESM value depending on the MCS selected for use. The EESM value calculated in this way maps the instantaneous state of the wireless channel to a singular value indicative of the quality of the channel. According to the techniques described herein, the calculated EESM value is then used to generate a quality indication, which itself is used to indicate a good or bad location of the underlying wireless device.

[0023] In different embodiments, different values ​​of the β parameter can be predetermined for a particular wireless device to take into account device characteristics such as form factor, antenna type, processing power (e.g., CPU type), etc. Table 1 below illustrates how different β parameter values ​​can be used for different MCSs when EESM metrics are used to predict the quality (e.g., throughput) of a wireless channel at a given location. Table 1. Example of throughput prediction for each MCS [Table 1]

[0024] In Table 1, the β parameter values ​​are calculated based on several simulations performed for several exemplary embodiments, in which several wireless channel modules were used to sweep through different symbol realizations, and a single power H for each i-th subcarrier of the simulated channel was calculated. i The EESM values ​​were then matched with different MCSs by trying different β parameter values ​​for an additive white Gaussian noise (AWGN) model used as a reference curve. In this way, for the purpose of calculating the β parameter value, these simulations ensure that the EESM values ​​are only strongly influenced by white noise, but are not influenced by any fading.

[0025] Table 1 also lists the most commonly used MCSs in wi-fi communications for symbol modulation and data bit coding. Wireless devices operating on VHT WLANs can use different rate adaptation mechanisms to select the best MCS under the given operating conditions of the device. For example, such rate adaptation mechanisms can be configured to select the highest possible MCS (because it provides the highest throughput) while taking into account high noise, weak signals, or any fades in the channel. Of the MCSs listed in Table 1, MCS0 is the most robust scheme because it uses binary phase shift keying (BPSK) coded with only one bit per symbol, whereas MCS1 uses quadrature phase shift keying (QPSK) coded with four bits per symbol, etc. MCS0 therefore requires a lower β parameter value than MCS1, since it requires a much lower SNR for proper operation. The technique described here pre-calculates the β parameter value for each MCS, which allows fine-tuning of the calculated EESM metric. Furthermore, the techniques described herein allow pre-calculated β parameter values ​​to be stored in a look-up table (LUT) within the wireless device, such that these parameter values ​​can be dynamically selected during operation of the device.

[0026] In different embodiments, the techniques described herein use different types of preambles of wireless packets to calculate the EESM value and, based thereon, provide a quality indication. For example, in some embodiments, the wireless device can be configured to continuously calculate the EESM value based on the preamble of any received PPDU and, based thereon, provide a quality indication. In some embodiments, the wireless device can be configured to calculate the EESM value based on the preamble of any received NDP, where the NDP can be transmitted from the access point repeatedly within a certain time window (e.g., during setup or configuration) to allow a user to find the best location for the wireless device (e.g., while installing a security camera).

[0027] The structure of a PPDU packet is illustrated in Figure 3A. PPDU 301A includes a legacy preamble field 304, a VHT preamble field 306, and a data field 308. The legacy preamble field 304 includes three preamble segments: a legacy-short training field (L-STF), a legacy-long training field (L-LTF), and a legacy-signal field (L-SIG). The legacy preamble segment stores training symbols (a set of one or more bits with a digital value of "-1" or "1") used by IEEE 802.11ax and all pre-802.11ax protocols for packet detection (also called frame detection). The data stored in the L-STF and L-LTF segments are used for packet identification and front-end synchronization, and the L-SIG segment stores the data rate and the length of the packet in bytes. The VHT preamble field 306 includes VHT-SIGA, VHT-STF, VHT-LTF and VHT-SIGB segments, which contain symbols for additional VHT format specific training and signaling. The VHT-SIGA segment contains actual rate values, channel coding, guard intervals, Multiple-Input Multiple-Output (MIMO) schemes and other configuration details for VHT format packets. The VHT-STF segment contains symbols used to improve automatic gain control estimation in MIMO transmissions. The VHT-LTF segment contains symbols used for MIMO channel estimation and pilot subcarrier tracking. The VHT-SIGB segment contains symbols used to set data rates and fine tune MIMO reception in multi-user situations. The data field 308 contains the payload of the PPDU 301A, which may include service bits, service data units, tail bits and pad bits.

[0028] Figure 3B illustrates the structure of two NDP packets transmitted together during the process of beamforming. (Beamforming is a transmission process that focuses the transmission energy towards the receiver.) NDP packet 301B includes an NDP announcement packet 302 followed by an NDP packet including a legacy preamble field 304 and a VHT preamble field 306. The NDP announcement packet 302 includes control information for the intended beamforming. The legacy preamble field 304 and the VHT preamble field 306 have the same format and contain the same information as the corresponding preamble fields of PPDU 301A. The NDP packet 301B does not have any payload and therefore does not include any data fields.

[0029] FIG. 4 illustrates a schematic diagram of the operational flow of quality indication logic configured for guided placement of a wireless device, according to an exemplary embodiment. As used herein, "logic" refers to a hardware block having one or more circuits including different electronic components configured to process analog and / or digital signals and perform one or more operations in response to control signals and / or firmware instructions executed by a central processing unit (CPU). Examples of such electronic components include, but are not limited to, transistors, diodes, logic gates, and different arrays and circuits thereof. In different embodiments, the quality indication logic can be implemented as a state machine, application specific circuits, and / or other logic blocks and analog / digital circuits that can be configured to control the hardware in response to control signals and / or firmware instructions. For example, the quality indication logic 430 of FIG. 4 can be implemented as a state machine configured to execute a sequence of states (operations) on a received wireless packet. These states in the quality indication logic 430 are implemented in baseband PHY (physical layer) hardware (e.g., logic gates, registers and other hardware circuits operating in the digital domain) that route and manage the flow of signals from one state to another.

[0030] During operation of the wireless device, an analog RF signal is received on a wireless channel and converted to a modulated digital signal. A wireless packet is extracted from the modulated digital signal, and the quality indication logic 430 of the wireless device is notified that the packet has been received (state 431). For example, a baseband processor logic (not shown) can receive and process the modulated digital signal and can notify the quality indication logic 430 accordingly by using an appropriate mechanism (e.g., a register, a shared memory, etc.). A correlation block correlates the STF of the received packet (state 433). A channel estimation block estimates (or otherwise identifies) the signal strength for each subcarrier of the wireless channel and sends the channel estimation data to a validation block of the quality indication logic 430 (state 435). The channel estimation data may also include both the phase and amplitude of individual OFDM subcarriers to capture interference caused by the shapes and / or compositions of different objects in the vicinity of the wireless device. The address block extracts (or otherwise identifies) the MAC (media access control) address of the received packet and sends the address data to the validation block (state 437). The noise estimation block estimates the SNR of the wireless channel and sends the SNR data to the EESM calculation block of the quality indication logic 430 (state 439). The validation block uses the channel estimation data and the address data to identify whether the received packet is a valid packet (e.g., whether the packet is not noise or interference and / or whether the packet belongs to a wireless device in the wireless channel), and passes the channel estimation data to the EESM calculation block if the packet is valid (state 441). The EESM calculation block looks up the β parameter of the MCS selected for the wireless packet in the LUT and calculates the EESM value based on the channel estimation data, the SNR data, and the β parameter value according to the above-mentioned equations (1) and (2) (state 443).In some embodiments, the calculated EESM value may be an average of several EESM values ​​(or may be otherwise derived from several EESM values) that can be calculated based on multiple symbols from the preamble of the same packet and / or based on symbols from the preambles of multiple packets. The calculated EESM value is passed to a quality indication block, which determines a quality indication that is output from the quality indication logic 430 (state 445). The output quality indication may be the calculated EESM value itself, or it may be some other data value or value derived from (or based on) the calculated EESM value.

[0031] For example, in some embodiments, the calculated EESM value can be provided as a throughput indication to a host application via a host interface of the wireless device. In these embodiments, the host application can be configured on the wireless device itself or on a separate device communicatively connected to the wireless device. In another embodiment, in state 445, the quality indication logic 430 can compare the calculated EESM value with a pre-specified data range (e.g., good, fair, or poor) to indicate channel quality and can output a quality indication value corresponding to the specified quality of the wireless channel. The quality indication value can then be provided (e.g., via a suitable API) to an application of the wireless device, which can set a corresponding wi-fi signal icon or wi-fi bar icon (e.g., for a wireless device with a display) or another type of visual indication such as an LED (for a wireless device without a display).

[0032] In this way, the techniques described herein predict the quality (e.g., throughput) of a wireless channel based on an EESM metric calculated based on training field data in the preamble of a wireless packet, such as a PPDU or NDP packet. Such training field data can be obtained from a legacy preamble or a VHT preamble. Thus, to predict the channel quality, it is sufficient for the AP to transmit and the wireless device to receive a wireless packet that includes only a preamble and may not include data.

[0033] FIG. 5 illustrates a flow diagram of a method for guided placement of a wireless device. The operations of the method of FIG. 5 are described as being performed by an access point device (AP) 10 and a wireless device (STA) 100 with quality indication logic of the wireless device (STA) 100 according to an exemplary embodiment. However, it should be noted that in different implementations and embodiments, different components, possibly different components, can be used to perform the operations of the method of FIG. 5. For example, in different embodiments, a system-on-chip (SoC) wi-fi device or a single-chip wi-fi / Bluetooth combo device can be configured with firmware instructions that, when executed by one or more processors or other hardware components (e.g., microcontrollers, state machines, and the like), are operable to perform the operations of the method of FIG. 5. In another example, in different embodiments, an integrated circuit (IC) device can include a single-chip or multi-chip wi-fi controller configured to perform the operations of the method of FIG. 5. Thus, the following description of the method of FIG. 5, as performed by a wireless device and / or logic thereof, should be considered in an illustrative sense, rather than a limiting sense.

[0034] In operation 501, the AP 10 transmits a wireless packet to the STA 100 via a wireless channel. For example, in some embodiments, the AP 10 may be configured to transmit a PPDU packet or another type of wireless packet with appropriate training data in a preamble field. In some embodiments, the AP 10 may be in a beamforming mode to send an NDP packet on the wireless channel. Because some channel vectors may become outdated in the process of beamforming, the AP 10 is configured to periodically send an NDP packet and receive feedback from the STA 100. This allows the STA 100 to receive a sufficient number of NDP packets to calculate a sufficient EESM value according to the techniques described herein.

[0035] In operation 503, the STA 100 receives a wireless packet over a wireless channel from the AP 10. For example, a transceiver in the STA 100 receives an analog RF signal and converts it to a modulated digital signal that is sent to a baseband processor that extracts the wireless packet from the modulated digital signal.

[0036] In operation 505, the STA 100 calculates an EESM value based on one or more received wireless packets according to the techniques described herein. For example, the quality indication logic of the STA 100 validates the received packet and estimates (or otherwise determines) the signal strength for each subcarrier of the wireless channel across selected symbols in the preamble of the received packet. The quality indication logic also estimates the SNR of the wireless channel and uses the LUT to find the β parameter value of the MCS for the received packet. The quality indication logic then calculates an EESM value based on the signal strength of each subcarrier, the SNR data, and the β parameter value according to the above-mentioned equations (1) and (2).

[0037] In operation 507, the quality indication is provided by the STA 100 to a host (or an application running thereon), which may be configurable on-chip or off-chip. For example, in some embodiments, the quality indication logic of the STA 100 can transmit the calculated EESM value itself as a quality indication value to the host. In some embodiments, the quality indication logic can convert the calculated EESM value to a quality indication value (e.g., good, fair, or poor) corresponding to the channel quality. Based on the quality indication value, the host can set a corresponding wi-fi signal icon or wi-fi bar icon (e.g., if the STA 100 has a display) or another type of visual indication, such as an LED (e.g., if the STA 100 does not have a display).

[0038] After operation 507, the method may proceed to be repeated multiple times with additional wireless packets being transmitted by the AP 10 and received by the STA 100. Alternatively or additionally, the method may be repeated after the STA 100 is moved to another location (operation 509). The change in the location of the STA 100 may include a change in the physical location of the STA 100 and / or a change in the orientation of the STA 100 or its antenna relative to the AP 10. In this manner, by repeating operations 503, 505, and 507, new EESM values ​​are periodically calculated that may correspond to the new location of the STA 100.

[0039] In some embodiments, the method of FIG. 5 can be used to select a location for a fixed-location wireless device (such as a security camera). Once the fixed-location device is installed, a new EESM value can be recalculated if location-related conditions change (e.g., an interference source is placed nearby). In some embodiments, the wireless device can use beacons transmitted from the AP (with or without data) to periodically calculate an EESM value representing the quality of the wireless channel. For example, the wireless device can use training symbols in the beacon or data packet preamble to continuously estimate the EESM value and subsequently visualize it on the wireless device. In this way, the wireless device can obtain a continuously updated quality visualization (such as a wi-fi bar or wi-fi signal icon).

[0040] The techniques for guided placement of wireless devices described herein can be implemented in various types of portable wireless devices, including wi-fi chipsets. An exemplary wireless device configured in accordance with the techniques described herein is illustrated in FIG. 6. In the embodiment illustrated in FIG. 6, the wireless device 600 may be a single-chip IC device fabricated on a semiconductor die or a single-chip IC fabricated as a System-on-Chip (SoC). In another embodiment, the wireless device 600 may be a multi-chip module encapsulated in a single semiconductor package. Thus, the wireless device 600 of FIG. 6 should be considered in an exemplary sense, rather than a limiting sense.

[0041] The wireless device 600 includes a CPU 652, a read-only memory (ROM) 654, a random access memory (RAM) 656, a host interface 658, a digital baseband PHY 620, and an RF transceiver 610. The CPU 652, the ROM 654, the RAM 656, the host interface 658, and the digital baseband PHY 620 are connected to one or more buses 650. The digital baseband PHY 620 is also connected to the RF transceiver 610, which is connected to at least one antenna 601. In some embodiments, the antenna may be integrally formed or embedded on the same IC chip with the remaining components of the wireless device 600, or may be located on a separate chip or substrate. Alternatively, the antenna may be separately connected to a printed circuit board (PCB) on which the wireless device 600 is attached or mounted.

[0042] CPU 652 includes one or more processing cores configured to execute instructions that may be stored in ROM 654, RAM 656, or flash memory (not shown). ROM 654 is a read-only memory (or another suitable storage medium) configured to store boot-up routines, configuration parameters, and other firmware parameters and settings. RAM 656 is a volatile memory configured to store data and firmware instructions accessed by CPU 652. Flash memory, if provided, may be an embedded or external non-volatile memory (e.g., NAND flash, NOR flash, etc.) configured to store data, programs, and / or other firmware instructions.

[0043] The host interface 658 may include control registers, data registers, and other circuitry configured to transfer data between the digital baseband PHY 620 and a host (not shown). The host may be a microcontroller subsystem located on the chip or may be an off-chip IC device. The host may include its own CPU operable to execute a host application or other firmware / software configured to receive and process quality indications in accordance with the techniques described herein (among other functions).

[0044] The bus 650 may include one or more buses, such as a system interconnect and a peripheral interconnect. The system interconnect may be a single-level or multi-level Advanced High-Performance Bus (AHB) configured as both an interface connecting the CPU 652 and other components of the wireless device 600 and as a data and control interface between the different components and the peripheral interconnect. The peripheral interconnect may be an Advanced eXtensible Interface (AXI) that provides a primary data and control interface between the CPU 652 and its peripherals and other resources (e.g., system resources, input / output (I / O) blocks, direct memory access (DMA) controllers, etc.), which is programmable to transfer data between peripheral blocks without burdening the CPU.

[0045] The digital baseband PHY 620 includes different logic blocks and circuits configured to process signals and data transferred between the RF transceiver 610 and different components connected to one or more buses 650. The digital baseband PHY 620 includes a TX BBP 622 and a RX BBP 624. The TX BBP 622 includes circuitry configured to receive digital data (e.g., a series of bytes) from other components of the wireless device 600 and convert the received data into a modulated digital signal that is transmitted to the RF transceiver 610. The RX BBP 624 includes circuitry configured to receive a modulated digital signal from the RF transceiver 610 and convert the received signal into digital data.

[0046] The RF transceiver 610 includes various logic blocks and circuits configured to process signals transferred between the digital baseband PHY 620 and the antenna 601. The RF transceiver 610 includes a transmitter circuit 612 and a receiver circuit 614. The transmitter circuit 612 includes a digital-to-analog converter (DAC) and other circuitry configured to receive a modulated digital signal from the TX BBP 622 and convert the modulated digital signal to an analog RF signal for transmission via the antenna 601. The receiver circuit 614 includes an analog-to-digital converter (ADC) and other circuitry configured to receive an analog RF signal from the antenna 601 and convert the analog RF signal to a modulated digital signal that is transmitted to the RX BBP 624.

[0047] In operation in the transmitter path, the TX BBP 622 receives a stream of data bytes from a component (e.g., CPU 652, host interface 658, etc.) via one or more buses 650. The TX BBP 622 converts the received bytes of data into packets with a preamble and a trailing CRC, scrambles the packets, and serializes the scrambled packets into a stream of data bits. The TX BBP 622 then phase modulates the stream of data bits onto the cosine (I) and sine (Q) portions of a modulated signal and transmits the modulated signal to the transmitter circuitry 612. The transmitter circuitry 612 converts the I and Q portions of the modulated signal to multiple analog signals using a DAC, combines the analog signals into an RF signal, and transmits the RF signal via the antenna 601.

[0048] In operation in the receiver path, the receiver circuitry 614 receives an RF signal from the antenna 601, converts the received RF signal using an ADC to the I and Q portions of a modulated digital signal, and transmits the modulated signal to the RX BBP 624. The RX BBP 624 recovers / traces the timing intervals and relative phase of the modulated signal and uses this timing information to demodulate the received signal into a stream of bits. The RX BBP 624 then deserializes the stream of bits, reassembles the bits into packets, and descrambles the packets. Any payload data in the packets is then converted into a series of bytes, which are transmitted over one or more buses 650 to components (e.g., CPU 652, host interface 656, etc.).

[0049] According to the techniques described herein, the RX BBP 624 includes a quality indication logic 430 configured to calculate an EESM value based on the preamble of a received packet and provide a radio channel quality indication to different components of the wireless device 600 (such as, for example, the CPU 652 and / or the host interface 658). The quality indication logic 430 of the RX BBP 624 is similar to the quality indication logic 430 illustrated in FIG. 4. In the embodiment illustrated in FIG. 6, the quality indication logic 430 is implemented as part of a programmable state machine (PSM), which is a microcoded engine that includes a highly optimized microcontroller for flow control operations and provides low-level control of different hardware circuits required to implement the IEEE 802.11 specification. For example, in operation, the PSM fetches instructions from a microcode memory, uses a shared memory to obtain operands for the instructions, and uses a scratchpad memory (similar to a register bank) to store frequently accessed and temporary variables. The PSM exercises fine-grained control over hardware circuitry by programming internal hardware registers (IHRs), which are co-located with the hardware functions they control.

[0050] In operation, the RX BBP 624 notifies the quality indication logic 430 when a wireless packet is received and descrambled. The quality indication logic 430 checks the validity of the received packet and estimates (or otherwise determines, for example, based on signal information from the receiver circuitry 614) the signal strength for each subcarrier of the wireless channel over selected symbols in the preamble of the received packet. The quality indication logic 430 also estimates the SNR of the wireless channel and accesses the LUT to find the β parameter value of the MCS for the received packet. The quality indication logic 430 then calculates an EESM value based on the signal strength of each subcarrier, the SNR data, and the β parameter value, and generates a quality indication value that represents the quality of the wireless channel on which the packet was received. The quality indication value can then be transmitted to the host interface 658, the CPU 652, or stored in the RAM 656. In some embodiments, the quality indication logic 430 can calculate the EESM value as an average of several EESM values ​​calculated based on multiple symbols from the preamble of the same packet and / or based on symbols from the preambles of multiple packets. In some embodiments, the quality indication logic 430 can transmit or store the calculated EESM value itself as the quality indication value. In another embodiment, the quality indication logic 430 can convert the calculated EESM value into a quality indication value corresponding to the channel quality (e.g., good, fair, or poor).

[0051] In various embodiments, the techniques for guided placement of wireless devices described herein can provide improved throughput performance, which can result in higher data rates, fewer retransmissions of data packets, and longer battery life for the devices. For example, in some embodiments, an access point device in the up-link (UL) can be configured to check the channel quality of a wireless device using EESM metrics and determine whether to hand off the wireless device to another access point device that has a better EESM than the device. In some embodiments, the EESM-based techniques described herein can also be used to address radio design issues such as beamforming, switched antenna diversity, and the use of polarized or directional antennas.

[0052] Different embodiments of the techniques for guided placement of wireless devices described herein may include different operations. These operations may be performed and / or controlled by hardware components, digital hardware and / or firmware and / or combinations thereof. As used herein, the term "connected to" may mean directly connected or indirectly connected through one or more intervening components. Any signal provided through different on-die buses may be time multiplexed with other signals and provided through one or more common on-die buses. Additionally, the interconnections between circuit components or blocks may be viewed as buses or as single signal lines. Each bus may alternatively be one or more single signal lines, and each single signal line may alternatively be a bus.

[0053] Some embodiments can be implemented as a computer program product that may include instructions stored in a non-transitory computer-readable medium, such as, for example, a volatile memory and / or a non-volatile memory. These instructions can be used to program and / or configure one or more devices including a processor (e.g., a CPU) or equivalent thereof (such as, for example, a processing core, a processing engine, a microcontroller, etc.), such that when executed by the processor or equivalent thereof, the instructions cause the device to perform the described operations for guided placement of a wireless device. The computer-readable medium may also include one or more mechanisms for storing or transmitting information in the form of (e.g., software, processing applications, etc.) that is readable by a machine (such as, for example, a device or a computer). Non-transitory computer-readable media may include, but are not limited to, electromagnetic storage media (e.g., floppy disks, hard disks, etc.), optical storage media (e.g., CD-ROMs), magneto-optical storage media, read-only memory (ROM), random-access memory (RAM), erasable programmable memory (e.g., EPROM and EEPROM), flash memory, or another now known or later developed non-transitory medium suitable for storing information.

[0054] Although the operations of the circuits and blocks herein are shown and described in a particular order, in some embodiments, the order of operations of the respective circuits / blocks may be changed such that certain operations may be performed in reverse order or certain operations may be performed, at least in part, simultaneously and / or in parallel with other operations. In other embodiments, instructions or sub-operations of different operations may be performed in an intermittent and / or alternating manner.

[0055] In the foregoing specification the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be apparent that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are therefore to be regarded in an illustrative rather than a restrictive sense.

Claims

1. A wireless device, comprising: an RF transceiver configured to receive a radio frequency (RF) signal transmitted over a wireless channel and convert the RF signal into a modulated digital signal; a baseband processor coupled to the RF transceiver; having The baseband processor includes at least receiving the modulated digital signal from the RF transceiver; Extracting a wireless packet including a preamble from the modulated digital signal; Calculating an Exponential Effective SNR Mapping (EESM) value indicative of the quality of the wireless channel at a current location of the wireless device based on the preamble of the wireless packet; providing a quality indication based on the EESM value for the current location of the wireless device. It is structured as follows: Subsequently, the wireless device is moved to a new location. Wireless devices.

2. To calculate the EESM value, the baseband processor is further configured to reference a β parameter value in a look-up table that stores pre-calculated β parameter values ​​for a plurality of modulation-and-coding schemes (MCSs). The wireless device of claim 1 .

3. In order to calculate the EESM value, the baseband processor is further configured to estimate a Signal-to-Noise Ratio (SNR) value for the wireless channel. The wireless device of claim 1 .

4. To calculate the EESM value, the baseband processor is further configured to use signal strength values ​​for each subcarrier of the wireless channel. The wireless device of claim 1 .

5. The baseband processor is further configured to determine that the wireless packet is valid. The wireless device of claim 1 .

6. the wireless device further having a display, and the quality indication is displayed on the display as a visual icon. The wireless device of claim 1 .

7. the wireless device further includes a plurality of light emitting diodes (LEDs), and the quality indication is displayed on the plurality of LEDs. The wireless device of claim 1 .

8. The baseband processor is further configured to periodically recalculate the EESM value. The wireless device of claim 1 .

9. The baseband processor is further configured to calculate a new EESM value and provide a new quality indication based on the new EESM value if the current location of the wireless device changes. The wireless device of claim 1 .

10. The wireless packet is a Null Data Packet (NDP) or a PHY Protocol Data Unit (PPDU), The wireless device of claim 1 .

11. receiving, by a wireless device at a first location over a wireless channel, a first wireless packet including a first preamble; calculating, by the wireless device, a first Exponential Effective SNR Mapping (EESM) value indicative of a first quality of the wireless channel at the first location based on the first preamble of the first wireless packet; providing, by the wireless device, a first quality indication based on the first EESM value for the first location of the wireless device; receiving, by the wireless device, a second wireless packet over the wireless channel at a second location different from the first location, the second wireless packet including a second preamble; calculating, by the wireless device, a second EESM value indicative of a second quality of the wireless channel at the second location based on the second preamble of the second wireless packet; providing, by the wireless device, a second quality indication based on the second EESM value for the second location of the wireless device; The method includes:

12. the steps of calculating the first EESM value and calculating the second EESM value include referencing one or more β parameters for one or more respective modulation-and-coding schemes (MCSs). The method of claim 11.

13. the step of calculating the first EESM value includes estimating a first signal-to-noise ratio (SNR) value for the wireless channel; and calculating the second EESM value includes estimating a second SNR value for the wireless channel. The method of claim 11.

14. the steps of calculating the first EESM value and calculating the second EESM value include determining a signal strength value for each subcarrier of the wireless channel. The method of claim 11.

15. The method comprises: determining that the first wireless packet is valid; determining that the second wireless packet is valid; Also includes The method of claim 11.

16. and wherein the steps of providing the first quality indication and providing the second quality indication include displaying a visual icon on a display of the wireless device. The method of claim 11.

17. the step of providing the first quality indication and the step of providing the second quality indication include driving a plurality of Light Emitted Diodes (LEDs) of the wireless device. The method of claim 11.

18. At least one of the first wireless packet and the second wireless packet is a Null Data Packet (NDP). The method of claim 11.

19. At least one of the first wireless packet and the second wireless packet is a PHY Protocol Data Unit (PPDU). The method of claim 11.

20. The method further comprises periodically calculating a current EESM value indicative of a current quality of the wireless channel at a current location of the wireless device. The method of claim 11.

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