Method for setting transmission power in a wireless device

Abstract

Methods and systems are disclosed for customizing the transmit power of a wireless device to parameters of the device, such as process split, voltage, and temperature. The device can identify one or more parameters of the device, such as identifying a process split, or sensing an operating voltage or temperature. The device can determine an updated transmit power based on the identified known parameter values and any unknown parameter values. When the device transmits based on the known parameter values and across a range of variations of the unknown parameter values, the updated transmit power is determined as the maximum transmit power that satisfies one or more target transmit metrics, such as EVM and spectral mask. The device can periodically adjust its transmit power based on the updated transmit power.

Description

[0001] Related Applications

[0002] This application is an international application of U.S. non - provisional application Ser. No. 16 / 586,243, filed on Sep. 27, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] The subject technology generally relates to wireless communication systems, and more particularly, to methods and systems for setting transmit power for devices operating in a wireless communication channel to increase transmission range based on the characteristics of the devices and the operating environment of the devices. Background Art

[0004] WLAN systems compliant with IEEE 802.11 (WiFi TM ) standards are used by a variety of devices, including increasingly by low - power Internet of Things (IoT) devices for communicating sensor data and other types of information. The transmission range and link budget of a wireless device are determined by the transmit power of the wireless device and other factors. The transmit power of a wireless device may be limited by regulatory constraints and device characteristics (e.g., the relationship between demodulation error and the transmit power of the device). For example, the transmit power must meet the adjacent - channel power - ratio (ACPR) requirements of the WiFi TM standard, which impose limitations on the spectral mask of transmissions from the device. Due to non - linearities of radio - frequency (RF) transmitters, etc., the transmit power is further limited by the error - vector magnitude (EVM) of different modulation and coding schemes. One way to increase the transmit power of a wireless device while maintaining compliance with regulatory power requirements could be, for example, to improve device characteristics by reducing the EVM or spectral - mask margin. However, such changes to the wireless device may result in penalties of increased complexity, cost, area, and power of the wireless device. For wireless devices that communicate using WLAN, Bluetooth, etc. and are in a wide - area network, it is desirable to increase the transmit power and the resulting transmission range without these drawbacks. Brief Description of the Drawings

[0005] The described embodiments and their advantages may best be understood by reference to the following description taken in conjunction with the accompanying drawings. These drawings in no way limit any changes in form and detail that a person skilled in the art may make to the described embodiments without departing from the spirit and scope of the described embodiments.

[0006] Figure 1 An example of a WLAN system in accordance with one embodiment of the present disclosure is shown, where a wireless device communicates with an access point (AP).

[0007] Figure 2Shows the relationship between EVM and transmit power for different process splits (which are process variations that statistically occur in the wafer manufacturing of integrated circuits) according to an embodiment of the present disclosure. For a modulation scheme, this relationship can be used to increase the transmit power according to the identified process split of a wireless device.

[0008] Figure 3 Shows a flowchart of a method for constructing an incremental transmit power array across process splits, operating temperatures, and operating voltages of wireless devices for different transmission modes and transmission rates according to an embodiment of the present disclosure.

[0009] Figure 4 Shows a flowchart of a method for using the incremental transmit power array to customize the transmit power of a wireless device according to the identified process split, sensed voltage, and sensed temperature of the device.

[0010] Figure 5 Is a diagram showing a wireless device operating at a nominal voltage and nominal temperature updating its transmit power according to an identified process split from a nominal process..

[0011] Figure 6 Is a diagram showing a wireless device updating its transmit power according to sensed voltage and sensed temperature from a nominal voltage and nominal temperature according to an embodiment of the present disclosure.

[0012] Figure 7 Is a block diagram of a wireless device according to an embodiment of the present disclosure, which senses operating voltage and operating temperature and identifies a process split to customize transmit power. Detailed Description

[0013] Examples of various aspects and variations of the subject technology are described herein and shown in the drawings. The following description is not intended to limit the invention to these embodiments, but to enable those skilled in the art to make and use the invention. For example, while examples, implementations, and embodiments of the subject technology are described using wireless devices operating in WLAN systems that comply with various versions of the IEEE802.11 (WiFi TM ) standard, the subject technology is not limited thereby and can be applied to other types of communication devices operating in other types of WLAN systems or wide area networks.

[0014] In WiFi TM The transmit power of a wireless device operating under the standard must comply with the transmission requirements imposed by the standards and regulatory authorities of the jurisdiction in which the wireless device operates and can meet the transmit metrics associated with the operation of the device. Device. For example, WiFiTM Standards have requirements for ACPR to limit interference to channels adjacent to the operating channel. ACPR is used as a target spectral mask to confine the power spectrum of a wireless device to the bandwidth of the operating channel. A wireless device may have its own transmit metrics, e.g., EVM and transmit power dynamic range. EVM measures the deviation of the constellation points of a signal modulation scheme from their ideal positions, which is caused by defects in the implementation of the wireless device's transmitter. To meet a given bit error rate for a modulation and coding scheme used for transmission at a given data rate, the EVM of the wireless device may not exceed the maximum EVM. Higher modulation and coding schemes for transmitting increasingly high data rates may have increasingly lower and thus more stringent maximum EVM requirements. The transmit power of a wireless device can be further limited to operate within a transmit power control (TPC) dynamic range to meet various error requirements.

[0015] The spectral mask and EVM of a wireless device can be functions of the device's transmit power, device parameters, and functional and operating characteristics. For example, higher transmit power generally results in larger EVM and lower spectral mask margin. Additionally, device parameters such as the manufacturing process split of an RF transmitter (which is a process variation that statistically occurs in the wafer fabrication of an RF transmitter), functional characteristics such as transmission mode and modulation and coding schemes, and operating characteristics such as supply voltage, ambient temperature, and junction temperature may affect the EVM and spectral mask. For a given combination of transmission mode and modulation and coding scheme (MCS), the maximum transmit power that meets the maximum EVM (referred to as the EVM compliance power) and the maximum transmit power that meets the target spectral mask (referred to as the SM compliance power) may vary across devices that are manufactured over a range of process splits and operate over a range of supply voltages and temperatures. A wireless device can operate with a transmit power that is the minimum of the EVM compliance power and the SM compliance power across the range of process split, possible operating voltages, and possible temperatures to ensure that the transmit power is always EVM and SM compliant, regardless of the actual process split, voltage, and temperature. However, most wireless devices operate within a relatively narrow range centered around the nominal voltage and nominal temperature. A wireless device can utilize known information about the process split, voltage, and temperature or a subset of these parameters to increase the transmit power and improve the range while complying with regulatory requirements and meeting the transmit metrics.

[0016] In one aspect of the subject technology, a wireless device can operate by leveraging transmit power that is customized to an actual operating voltage or temperature, or both voltage and temperature, where the transmit power has been characterized as being EVM and SM compliant for one or both of the actual operating voltage and temperature. For example, to customize the transmit power to only the actual operating voltage, the wireless device can operate using the EVM and SM compliant power that has been characterized as the minimum of the EVM compliant power and the SM compliant power over the actual operating voltage, a range of possible temperatures, and a range of process splits. Similarly, to customize the transmit power to only the actual temperature, the wireless device can operate using the EVM and SM compliant power that is characterized as the minimum of the EVM compliant power and the SM power over the actual temperature, a range of possible voltages, and a range of process splits. And to customize the transmit power to both the actual voltage and the actual temperature, the wireless device can operate using the EVM and SM compliant power that is characterized as the minimum of the EVM compliant power and the SM compliant power over the actual operating voltage, the actual temperature, and a range of process splits. In one embodiment, there may be a margin or tolerance associated with one or more of the EVM and SM compliant power. The tolerance of the EVM or SM compliant power can also be a function of device parameters as well as the functional and operational characteristics of the device. In one embodiment, the tolerance of the EVM, SM compliant power, or other Tx metric can be programmed based on device parameters as well as the functional and operational characteristics of the device. When customizing the transmit power, the wireless device can consider the tolerance of the EVM and SM compliant power for the actual operating voltage and actual temperature. Because the transmit power that has been characterized as EVM and SM compliant for one or both of the actual operating voltage and temperature cannot be lower than the EVM and SM compliant power over the range of process splits, all possible operating voltages, and all possible temperatures - and for a device operating near nominal voltage and temperature, the EVM and SM compliant transmit power is most likely higher - the wireless device can transmit at a higher power, thereby increasing the transmission range and link budget.

[0017] In one aspect of the subject technology, the wireless device can additionally identify a process split to customize the transmit power to the identified process split, actual operating voltage, and actual temperature. The wireless device can operate using the EVM and SM compliant power that has been characterized as the minimum of the EVM compliant power and the SM compliant power for the actual operating voltage, actual temperature, and the identified process split.

[0018] In one aspect of the subject technology, a wireless device can store a multi-dimensional array of transmit power information for use as EVM and SM compliance power for ranges of quantization process splits, quantization voltage steps, and quantization temperature steps for each combination of transmission mode and MCS. An offline device characterization operation can measure EVM and SM compliance power for each point in the multi-dimensional array. In one embodiment, the device characterization operation can construct a 5-dimensional array that includes process split, voltage, temperature, transmission mode, and data rate as dimensions. Each point in the 5-dimensional array can represent the difference between the EVM and SM compliance power for the combination of transmission mode and data rate represented by that point and the EVM and SM compliance power for a reference operating point (e.g., nominal process split, nominal voltage, and nominal temperature) for the combination of that transmission mode and data rate. Each point in the 5-dimensional array or each point in a 3-dimensional sub-array for a particular combination of transmission mode and data rate can be referred to as the incremental transmit power of that point relative to the reference operating point. In other embodiments, the array can have additional dimensions, e.g., operating channel, operating bandwidth, TPC dynamic range, or other functional and operating characteristics of the wireless device.

[0019] The wireless device can be powered on to transmit using the transmit power associated with a reference operating point (e.g., a previously identified nominal process split, nominal voltage, and nominal temperature). When information about the process split, actual voltage, or actual temperature is known, the wireless device can use that information to eliminate dimensions from the search space when searching the multi-dimensional array for the minimum of the incremental transmit power when determining the transmit power. For example, when the actual voltage of the wireless device is known, the wireless device can avoid searching all possible voltages by setting the voltage to the actual voltage and can search in the two dimensions of the range of process splits in the multi-dimensional array and all possible temperatures to find the minimum incremental transmit power for the combination of transmission mode and data rate. The wireless device can then adjust its transmit power from the reference operating point by the minimum incremental transmit power found, thus ensuring that the transmit power will be EVM and SM compliant regardless of the actual process split and temperature.

[0020] Similarly, when both the actual voltage and temperature of the wireless device are known, the wireless device can avoid searching all possible voltages and all possible temperatures by setting the voltage to the actual voltage and setting the temperature and can search only the process split dimension of the multi-dimensional array to find the minimum incremental transmit power for the combination of transmission mode and data rate. The wireless device can then adjust its transmit power from the reference operating point by the minimum incremental transmit power found, thus ensuring that the transmit power will be EVM and SM compliant regardless of the actual process split.

[0021] When the process split, voltage, and temperature are all known, the wireless device can identify the incremental transmit power for the known process split, voltage, and temperature from a multidimensional array. The wireless device can then adjust its transmit power from a reference operating point by the incremental transmit power. The wireless device can identify the process split of the device by measuring the oscillator frequency using a ring oscillator. The firmware of the wireless device can use the measured ring oscillator frequency to look up a table that contains the relationship between the frequency and the process split. In one embodiment, the process split of the wireless device can be identified during manufacturing of the wireless device and programmed into the on-chip non-volatile memory to be read out by the firmware of the wireless device during operation. The wireless device can sense the operating voltage or the supply voltage by using an on-chip or an external sensor. To sense the temperature, the wireless device can use an on-chip temperature sensor, a thermistor, etc., placed near a hot spot of the device. Since the voltage and the temperature may change over time, the wireless device can periodically sense the voltage and the temperature to update the incremental transmit power from the multidimensional array and thus adjust the transmit power.

[0022] In one embodiment, a method for setting the transmit power of a wireless device includes: initializing the transmit power of the device to an initial transmit power. The transmit power is associated with one or more transmit metrics. The method further includes: identifying values of one or more parameters of the device to generate one or more known parameter values. The method can determine an updated transmit power based on the known parameter values and any parameter whose value is unknown. When the wireless device transmits based on the known parameter values and across a range of values of the unknown parameter, the updated transmit power can be determined as the maximum transmit power that satisfies a target transmit metric. The device can adjust its transmit power based on the updated transmit power. In one embodiment, the device can be a WLAN device that complies with any version of the IEEE 802.11 (WiFi TM ) standard.

[0023] In another embodiment, a wireless device is configured to implement a method for setting the transmit power of the wireless device to account for known and unknown parameter values, e.g., the operating and functional characteristics of the wireless device. The method can be implemented by a controller. The wireless device can include one or more antennas that are configured to transmit packets on a communication channel using the transmit power.

[0024] Figure 1 An example of a WLAN system according to an embodiment of the present disclosure is shown, in which a wireless device communicates with an access point (AP). The WLAN system can be an IEEE 802.11 (WiFi TM)Any version of the standard. The wireless device 105 is a user equipment (also known as a user station (STA)), which is configured to be associated with the AP 107. In one embodiment, the STA 105 can be a sensor configured to perform measurements or collect environmental information, for example, an IP security camera that captures video of the surrounding area, or a portable communication device operating over a local area network or a wide area network, such as a smart phone. The STA 105 and the AP 107 can form a basic service set (BSS). Once associated with the AP 107, the STA 105 can receive commands from the AP 107 and can send data to the AP 107.

[0025] The transmit power of the wireless device (whether it is the STA 105 or the AP 107) determines the transmission range. Since the STA 105 can be a low-power portable device, the STA 105 can have a lower transmit power capability compared to the AP 107. For example, the STA 105 may be able to transmit at a maximum transmit power of 16 dBm per antenna at the lowest data rate, while the AP may be able to transmit up to 21 dBm per antenna. The coverage area 108 of the AP 107 is thus larger than the coverage area 106 of the STA 105. If the STA 105 is located at the edge of the coverage area 108 of the AP 107, the STA 105 can receive the downlink (DL) transmission 110 from the AP 107, but the AP 107 cannot receive the uplink (UL) transmission 111 from the STA 105, thus creating an asymmetric link. The transmit power from the STA 105 is also limited by the spectral mask of the WiFi TM standard and the maximum EVM of the transmission mode and MCS used for transmission. The EVM and SM compliance power are functions of the process split, operating voltage, and operating temperature of the wireless device. Embodiments of the present disclosure utilize information about one or more of the process split, operating voltage, and operating temperature of the STA 105 to increase the EVM and SM compliance power of the STA 105, thereby increasing the coverage area 106 of the STA 105 and reducing the asymmetry of the two-way link. Information about other functions or operating characteristics of the wireless device can be similarly utilized to increase the EVM and SM compliance power.

[0026] Figure 2Shows the relationship between the EVM and the transmit power of a wireless device operating at a nominal voltage and nominal temperature at an MCS or data rate with different process splits. Each curve plots the EVM as a function of the measured transmit power for one process split. Examples of process splits include fast / fast, fast / slow, slow / fast, slow / slow, typical / typical, etc., where the first symbol of the pair represents the speed of the NMOS device and the second symbol of the pair represents the speed of the PMOS device. For any process split, the EVM increases as the transmit power increases. To meet the given bit error rate of the MCS, a maximum EVM of -32 dB is specified. When operating at an MCS, the wireless device may not transmit at a power that causes the EVM to exceed the maximum EVM. The maximum transmit power that results in the maximum EVM is the EVM compliance power. For example, a device with a fast / fast process split has an average EVM compliance power of 12 dBm and a worst EVM compliance power of 10.2 dBm. A device with a typical / typical process split has an average EVM compliance power of 13.2 dBm and a worst EVM compliance power of 12.6 dBm. The lower average EVM compliance power of the fast / fast process split is due to the higher EVM of the fast / fast process split compared to the typical / typical split process with the same transmit power setting, resulting in the device with the fast / fast process split reaching the maximum EVM at a lower transmit power.

[0027] Figure 2 Shows that the fast / fast process split has the lowest average EVM compliance power and the lowest worst EVM compliance power among all process splits. A wireless device with an unknown process split may be forced to transmit at the lowest worst EVM compliance power (i.e., 10.2 dBm) when operating at a nominal voltage and nominal temperature for a given MCS to ensure that its transmit power is EVM compliant, even if the device is actually a fast / fast process split. However, if it is known that the wireless device is a typical / typical process split, the device may transmit at the higher worst EVM compliance power of the typical / typical process split (i.e., 12.6 dBm). Therefore, having information about the process split of the device can allow the device to transmit at a higher EVM compliance power than otherwise.

[0028] Similarly, in the case of assuming a nominal process split, wireless devices operating at different voltages and temperatures can exhibit different functions of EVM versus measured transmit power, resulting in different EVM compliance powers. A wireless device that does not know its voltage and temperature may be forced to transmit at the lowest EVM compliance power across a range of voltages and temperatures to ensure that its transmit power is EVM compliant across that range. However, if information about one or both of the voltage or temperature of the wireless device is known, the device can transmit at a higher EVM compliance power because the range of voltages and temperatures over which the lowest EVM compliance power is determined becomes narrower. For example, if the voltage is known, the lowest EVM compliance power is determined based on the minimum of the EVM compliance powers across the temperature range corresponding to the known voltage rather than across the range of both temperature and voltage. Conversely, if the temperature is known, the lowest EVM compliance power is determined based on the minimum of the EVM compliance powers across the voltage range corresponding to the known temperature.

[0029] The spectral mask (SM) margin also decreases as the transmit power increases. Wireless devices operating at different voltages and temperatures and having different process splits can also exhibit different functions of SM versus transmit power, resulting in different SM compliance powers. A wireless device can similarly utilize information about one or more parameters of the process split, voltage, or temperature of the wireless device to determine the lowest SM compliance power over a narrower range of variation of the unknown parameter corresponding to the one or more known parameters. The transmit power of the wireless device needs to be EVM and SM compliant and can be determined based on the lower of the EVM compliance power and the SM compliance power for a given MCS. In one embodiment, the EVM compliance power can determine the transmit power for a higher MCS used for higher data rates because the EVM compliance power is typically lower than the SM compliance power at the higher MCS. On the other hand, the SM compliance power can determine the transmit power for a lower MCS used for lower data rates because the SM compliance power is typically lower than the EVM compliance power at the lower MCS.

[0030] Figure 3FIG. 300 is a flowchart of a method for constructing a multi-dimensional array of incremental transmit power across process splits, operating temperatures, and operating voltages for different transmission modes and transmission rates in accordance with an embodiment of the present disclosure. The incremental transmit power for a point in the array can represent the difference between the Tx power compliant with the metrics corresponding to that point and the Tx power compliant with the metrics for a reference operating point. Offline device characterization operations can construct a multi-dimensional array for a device (e.g., a board of an RF integrated chip or an RF transceiver for which the Tx power compliant with its metrics is to be determined) by measuring and statistically characterizing a plurality of devices across ranges of process splits, operating temperatures, and operating voltages, etc. for different transmission modes and transmission rates. Offline device characterization operations can be performed during device verification and performance characterization in a test facility, laboratory, field, etc. A wireless device can use information from the multi-dimensional array during device operation to determine EVM and SM compliant power.

[0031] At operation 301, the method measures the Tx power compliant with the Tx metrics across ranges of process splits, voltages, and temperatures for the device. The ranges of process splits, voltages, and temperatures can be quantized into a finite number of discrete steps. The Tx metrics can include maximum EVM, target ACPR, or SM, or other regulatory emission requirements. The method can characterize the Tx power compliant with the metrics for each combination of data rate and transmission mode. In one embodiment, the data rate can correspond to the MCS used for transmission. The transmission mode can include various modes that the device can support. For example, the transmission mode can include multiple-input multiple-output (MIMO) antenna transmission, single-input single-output (SISO) antenna transmission, space-time block code (STBC) antenna transmission, beamforming (BF) antenna transmission, and operating parameters such as operating channel, operating frequency, operating bandwidth, etc. The Tx power compliant with the metrics transmitted at the process splits, voltages, and temperatures for the device at the data rate and transmission mode is the maximum transmit power that satisfies all Tx metrics for that combination of process splits, voltages, temperatures, data rate, and transmission mode.

[0032] At operation 302, the method creates a multi-dimensional array for the device. In one embodiment, the multi-dimensional array can have five dimensions, including the process split, voltage, temperature, data rate, and transmission mode of the device. In other embodiments, the multi-dimensional array can have additional dimensions, which can include operating channel, operating frequency, operating bandwidth, TPC dynamic range, etc.

[0033] At operation 303, the method fills a multi-dimensional array with incremental transmit power for points in an array. The incremental transmit power for a point in the array can represent the difference between the Tx power compliant with a metric for a combination of process split, voltage, temperature, data rate, and transmission mode corresponding to the point and the Tx power compliant with the metric for a reference operating point. In one embodiment, each combination of data rate and transmission mode can have a reference operating point specific to that combination. For example, the reference operating point for a combination of data rate and transmission mode can be specified as the nominal process split for a typical / typical process, a nominal voltage of 3V, and a nominal temperature of 25°C. Then, the Tx power compliant with the metric for the reference operating point for the combination of data rate and transmission mode can be the Tx power compliant with the metric when a device with a nominal process split, nominal voltage, and nominal temperature operates at the combination of data rate and transmission mode. Thus, when the device operates with parameters different from the reference operating point, the multi-dimensional array of incremental transmit power indicates the offset of the Tx power compliant with the metric from the Tx power compliant with the metric for the reference operating point.

[0034] Figure 4 FIG. 4 shows a flowchart of a method 400 for customizing the transmit power of a wireless device based on an identified process split, sensed voltage, and sensed temperature of the device using an incremental transmit power array, according to one embodiment of the present disclosure. Method 400 may be performed by processing logic that may include hardware (e.g., circuitry, dedicated logic, programmable logic, processing device, etc.), software (e.g., instructions running / executing on a processing device), firmware (e.g., microcode), or a combination thereof. In some embodiments, method 400 may be performed by a wireless device (e.g., Figure 1 the STA 105 shown in FIG. 1), by another device remote from the wireless device, or by Figure 1 the AP 107 shown in FIG. 1.

[0035] At operation 401, the method initializes the device to operate with the Tx power compliant with the metric for a reference operating point. The Tx power compliant with the metric for the reference operating point may vary for different combinations of data rate and transmission mode. In one embodiment, the method may initialize the device to the Tx power compliant with the metric for a reference operating point corresponding to a combination of nominal data rate and nominal transmission mode. The reference operating point may be different from the actual operating point of the device.

[0036] At operation 402, the method identifies a process split of the device. In one embodiment, the method can identify the process split of the device by measuring the ring oscillator frequency using a ring oscillator. The wireless device can use the measured ring oscillator frequency to look up a table containing the relationship between the oscillator frequency and the process split to determine the process split. In one embodiment, the process split of the wireless device can be identified during manufacturing of the wireless device and programmed into an on-chip non-volatile memory. The wireless device can read the non-volatile memory to determine the process split.

[0037] At operation 404, the method periodically senses the voltage of the device. The voltage can be the supply voltage to the device or the operating voltage local to the RF circuitry of the device. The method can use an on-chip or external sensor to sense the voltage. In one embodiment, the period of the voltage sensing can be set to a programmable value, e.g., 1 second. In one embodiment, the method can use interrupt handling to sense the voltage.

[0038] At operation 405, the method periodically senses the temperature of the device. The temperature can be the junction temperature near a hot spot of the device or the ambient temperature. The method can use an on-chip temperature sensor, a thermistor, etc. to sense the temperature. The period of the temperature sensing can also be programmable. In one embodiment, the method can use interrupt handling to sense the temperature. The period of the temperature sensing and the period of the voltage sensing can be different such that the sensing of the temperature and the voltage can be performed independently of each other.

[0039] At operation 406, the method updates the transmit power adhered to by the metrics of the device for the operating transmission mode and data rate based on a multi-dimensional array of incremental transmit power and the identified process split, sensed voltage, and sensed temperature. For example, the method can determine the incremental transmit power based on the point in the multi-dimensional array corresponding to the identified process split, sensed voltage, and sensed temperature. The method can then adjust its transmit power from a reference operating point by the incremental transmit power to customize its transmit power to the identified parameters.

[0040] In one embodiment, when one or more of the parameters of the process split, sensed voltage, and sensed voltage are indeterminable or unknown, the method can search the multi-dimensional array of incremental transmit power to determine the minimum value of the incremental transmit power over the range of the unknown parameter corresponding to one or more known parameters. For example, if the temperature and the process split are identified but the voltage is unknown, the method can determine the minimum value of the incremental transmit power across the temperature range in the multi-dimensional array corresponding to the known voltage and the identified process split. The method can adjust its transmit power from the reference operating point by the found minimum incremental transmit power to customize its transmit power to the known voltage and the identified process split.

[0041] In one embodiment, when periodically sensing voltage and temperature, during continuous updates of the transmit power, the method can determine the difference between the incremental transmit power of the current iteration and the previous iteration. The method can adjust the transmit power based on the difference found between the iterations. For example, if for the previous sensed voltage and temperature, the incremental transmit power (e.g., the difference between the Tx power compliant with the metric at the previous iteration and the Tx power compliant with the metric at the reference operating point) is determined to be x, and for the current sensed voltage and temperature, the incremental transmit power is determined to be y, then the method can adjust the transmit power of the current iteration by (y - x).

[0042] Figure 5 FIG. is a diagram showing a wireless device operating at a nominal voltage and nominal temperature updating transmit power according to an identified process split from a nominal process in accordance with one embodiment of the present disclosure. The device can be initialized to operate with a Tx power 502 compliant with the metric for a reference operating point represented by a nominal process split of typical / typical process, a nominal voltage of 3V, and a nominal temperature of 25°C. When the device identifies its process split as a slow / slow process and determines that the device is operating with the nominal voltage and nominal temperature, the device can read the incremental transmit power from a multidimensional array corresponding to the slow / slow process, the nominal 3V voltage, and the nominal 25°C temperature. The device can adjust its transmit power by the incremental transmit power to customize its transmit power 504 for the slow / slow process.

[0043] Figure 6 FIG. is a diagram showing a wireless device updating transmit power based on sensed voltage and sensed temperature from a nominal voltage and nominal temperature in accordance with one embodiment of the present disclosure. Again, the device can be initialized to operate with a Tx power 602 compliant with the metric for a reference operating point represented by a nominal process split of typical / typical process, a nominal voltage of 3V, and a nominal temperature of 25°C. When the device identifies its process split as a typical / typical process and determines that the device is operating at 3.V and 0°C, the device can read the incremental transmit power from a multidimensional array corresponding to the typical / typical process, a 3.5V voltage, and the nominal 25°C temperature. The device can adjust its transmit power by the incremental transmit power to customize its transmit power 604 for the sensed voltage and temperature.

[0044] Figure 7 FIG. is a block diagram of a wireless device 701 that customizes transmit power for a split process, sensed voltage, and sensed temperature of the device in accordance with some embodiments of the present disclosure. The wireless device 701 can be Figure 1 the STA or AP 107.

[0045] Wireless device 701 may include WLAN hardware 703 and WLAN driver 705. WLAN driver 705 may include a WLAN Tx / Rx controller 715, an incremental Tx power array 719, a process split identification module 713, temperature and voltage sensors 709, and a Tx power update module 711. The incremental Tx power array 719 may be stored in a memory as a multi-dimensional array of incremental transmit power with respect to each combination of transmission mode and data rate as reference operating points. The process split identification module 713 may be a ring oscillator configured to determine the process split of device 701. The temperature and voltage sensors 709 may be circuits configured to sense the temperature and voltage of device 701. The Tx power update module 711 may be configured to update the transmit power complied with by the metrics of device 701 for a combination of operating transmit mode, data rate, operating channel, frequency, and bandwidth, etc., based on the multi-dimensional array of incremental transmit power and the identified process split, sensed voltage, and sensed temperature. The WLAN Tx / Rx controller 715 may be configured to control various modules to perform Figure 4 the operations of the method. The WLAN hardware 703 may be configured to transmit data packets from antenna 721 using the transmit power complied with by the metrics.

[0046] In one embodiment, wireless device 701 may include a memory and a processing device (not shown). The memory may be a synchronous dynamic random access memory (DRAM), a read-only memory (ROM), or other types of memory, which may be configured to store code to perform the functions of WLAN driver 705. The processing device may be provided by one or more general-purpose processing devices (e.g., a microprocessor, a central processing unit, etc.). In an illustrative example, the processing device may include a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or a processor implementing other instruction sets or a combination of instruction sets. The processing device may also include one or more dedicated processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), a network processor, etc. According to one or more aspects of the present disclosure, the processing device may be configured to perform the operations described herein to execute the operations and steps discussed herein.

[0047] Unless otherwise explicitly stated, terms such as "receive", "generate", "verify", "execute", "correct", "identify", etc. refer to actions and processes performed or implemented by a computing device that manipulate data represented as physical (electronic) quantities within the registers and memories of the computing device and transform it into other data similarly represented as physical quantities within the memory or registers of the computing device or other such information storage, transmission, or display devices.

[0048] The examples described herein also relate to apparatus for performing the operations described herein. The apparatus may be specially constructed for the required purposes or the apparatus may comprise a general purpose computing device selectively programmed by a computer program stored in a computing device. Such a computer program may be stored in a non-transitory computer-readable storage medium.

[0049] Certain embodiments may be implemented as a computer program product that may include instructions stored on a machine-readable medium. These instructions may be used to program a general purpose or special purpose processor to perform the described operations. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), such as, for example, software, a processing application. A machine-readable medium may include, but is not limited to, magnetic storage medium (e.g., a floppy disk); optical storage medium (e.g., a CD-ROM); magneto-optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; or another type of medium suitable for storing electronic instructions. A machine-readable medium may be referred to as a non-transitory machine-readable medium.

[0050] The methods and illustrative examples described herein are not inherently related to any particular computer or other apparatus. Various general purpose systems may be used in accordance with the teachings described herein, or it may prove convenient to construct a more specialized apparatus to perform the desired method steps. The structure required for various of these systems will appear as set forth in the above description.

[0051] The above description is intended to be illustrative and not restrictive. Although the present disclosure has been described with reference to specific illustrative examples, it will be recognized that the present disclosure is not limited to the examples described. The scope of the present disclosure should be determined with reference to the appended claims and the full scope of equivalents to which the claims are entitled.

[0052] As used herein, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms as well. It should also be understood that the terms "comprises", "comprising", "includes", and / or "including", when used herein, specify the presence of the recited features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Further, as used herein, the terms "first", "second", "third", "fourth", etc. are intended as labels to distinguish different elements and may not necessarily have the meaning of an order according to their numerical designation. Thus, the terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0053] It should also be noted that in some alternative implementations, the recited functions / acts may not occur in the order shown in the figures. For example, depending on the functions / acts involved, two figures shown in succession may in fact be executed substantially simultaneously or may sometimes be executed in the reverse order.

[0054] Although method operations are described in a particular order, it should be understood that other operations may be performed between the operations described, the described operations may be adjusted so that they occur at slightly different times, or the described operations may be distributed in a system that allows the processing operations to occur at various intervals associated with the processing.

[0055] Various units, circuits, or other components may be described or claimed as "configured to" or "configurable to" perform one or more tasks. In such contexts, the phrases "configured to" or "configurable to" are used to imply structure by indicating that the unit / circuit / component includes a structure (e.g., circuitry) that performs one or more tasks during operation. Thus, a unit / circuit / component can be considered configured to perform a task, or configurable to perform a task, even when the specified unit / circuit / component is not currently operating (e.g., not powered on). Units / circuits / components used in conjunction with "configured to" or "configurable to" language include hardware, such as circuitry, memory storing program instructions executable to implement the operations, etc. Reciting that a unit / circuit / component "is configured to" perform one or more tasks, or "is configurable to" perform one or more tasks, is expressly intended not to invoke 35 USC 112, paragraph 6, with respect to that unit / circuit / component. Additionally, "configured to" or "configurable to" can include a general-purpose structure (e.g., a general-purpose circuit) that is manipulated by software and / or firmware (e.g., an FPGA or a general-purpose processor executing software) to operate in a manner capable of performing the task(s) under discussion. "Configured to" can also include adapting a manufacturing process (e.g., a semiconductor manufacturing facility) to fabricate a device (e.g., an integrated circuit) suitable for implementing or performing one or more tasks. "Configurable to" is expressly intended not to apply to blank media, unprogrammed processors, or unprogrammed general-purpose computers, or unprogrammed programmable logic devices, programmable gate arrays, or other unprogrammed devices, unless accompanied by a programmed medium that imparts the ability to the unprogrammed device to be configured to perform the disclosed functions.

[0056] For purposes of explanation, the above description has been presented with reference to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to best explain the principles of the embodiments and their practical application to enable others skilled in the art to best utilize the embodiments and various modifications suitable for the particular use contemplated. Accordingly, the embodiments are considered illustrative rather than restrictive, and the invention is not limited to the details given herein but may be modified within the scope of the appended claims and equivalents thereof.

Claims

1. A method of operating a wireless device, comprising: Initializing, by the wireless device, a transmit power of the wireless device to an initial transmit power, the transmit power being associated with one or more transmit metrics; Identifying, by the wireless device, a value of each of one or more parameters among a plurality of parameters of the wireless device; Determining, by the wireless device, an updated transmit power based on the identified parameter values among the plurality of parameters and a range of values of each of any other parameters, the updated power being determined as the maximum transmit power at which an associated transmit metric satisfies one or more target transmit metrics when the wireless device transmits based on the identified parameter values and across the range of values of each of the other parameters, wherein each other parameter corresponds to a parameter for which a value associated with the wireless device cannot be identified by the wireless device; and Adjusting, by the wireless device, the transmit power based on the updated transmit power.

2. The method according to claim 1, wherein, The plurality of parameters includes process splitting, voltage, and temperature of the wireless device.

3. The method according to claim 1, wherein The one or more transmit metrics includes a spectral mask (SM).

4. The method according to claim 3, wherein The one or more transmit metrics further includes error vector magnitude (EVM) and transmit power control (TPC) dynamic range.

5. The method according to claim 3, wherein, The updated power being determined as the maximum transmit power at which an associated transmit metric satisfies the one or more target transmit metrics when the wireless device transmits based on the identified parameter values and across the range of values of each of the other parameters includes: the updated power being determined as the maximum transmit power for which, for the identified parameter values and the range of values of each of the other parameters, the associated SM and EVM do not exceed a maximum EVM and a target SM, respectively.

6. The method according to claim 5, wherein, The SM and the EVM associated with the maximum transmit power do not exceed one or more tolerance values of the maximum EVM and the target SM, respectively.

7. The method according to claim 1, wherein Determining, by the wireless device, an updated transmit power based on the identified parameter values and a range of values of each of any other parameters includes: determining the updated transmit power according to a multidimensional array of incremental transmit powers corresponding to a range of values of each of the plurality of parameters of the wireless device, wherein the incremental transmit power corresponding to each combination of values of the plurality of parameters is characterized such that the transmit metric associated with the transmit power can satisfy the one or more target transmit metrics.

8. The method according to claim 7, wherein The multidimensional array is constructed according to the plurality of parameters of the wireless device, wherein the plurality of parameters includes data rate and transmit mode of the wireless device.

9. The method according to claim 8, wherein The plurality of parameters in the multidimensional array further includes operating frequency and operating bandwidth of the wireless device.

10. The method according to claim 7, wherein, The incremental transmit power corresponding to each combination of changes in the plurality of parameters in the multidimensional array is characterized relative to the initial transmit power.

11. The method according to claim 10, wherein, The initial transmit power corresponds to nominal values of the plurality of parameters, and wherein when the plurality of parameters of the wireless device are at the nominal values, the initial transmit power enables the associated transmit metric(s) to meet the one or more target transmit metrics.

12. The method according to claim 7, wherein, Determining the updated transmit power based on the multi-dimensional array of incremental transmit power includes: determining as the updated transmit power the minimum value of the incremental transmit power corresponding to the identified parameter value and across the range of values of each of the other parameters.

13. The method according to claim 1, wherein Identifying, by the wireless device, the value of each of the one or more parameters of the plurality of parameters of the wireless device includes: periodically identifying one or more parameter values, and wherein determining, by the wireless device, the updated transmit power based on the identified parameter values of the plurality of parameters and the range of values of each of any other parameters includes: periodically determining the updated transmit power based on the one or more identified parameter values periodically identified and the range of values of each of the other parameters.

14. The method according to claim 1, wherein, The wireless device includes a Wireless Local Area Network (WLAN) device.

15. A wireless device, comprising: a memory; and a processing device operably coupled to the memory, the processing device configured to: initialize a transmit power of the wireless device to an initial transmit power, the transmit power being associated with one or more transmit metrics; identify the value of each of one or more parameters of the plurality of parameters of the wireless device; determine an updated transmit power based on the identified parameter values of the plurality of parameters and the range of values of each of any other parameters, the updated power being determined as the maximum transmit power for which the associated transmit metric(s) meet one or more target transmit metrics when the wireless device transmits based on the identified parameter values and across the range of variation of values of each of the other parameters, wherein each other parameter corresponds to a parameter for which the value associated with the wireless device respectively cannot be identified by the wireless device; and adjust the transmit power based on the updated transmit power.

16. The wireless device according to claim 15, wherein, The plurality of parameters includes process splitting, voltage, and temperature of the wireless device.

17. The wireless device according to claim 15, wherein, The processing device is configured to identify the value of each of the one or more identified parameters of the plurality of parameters of the wireless device by using one or more of the following: a ring oscillator circuit or non-volatile memory configured to identify process splitting; a voltage sensor configured to sense voltage; or a temperature sensor configured to sense temperature.

18. The wireless device according to claim 15, wherein, The one or more transmit metrics includes a Spectrum Mask (SM).

19. The wireless device according to claim 18, wherein, The one or more transmit metrics further includes Error Vector Magnitude (EVM) and Transmit Power Control (TPC) dynamic range.

20. The wireless device according to claim 18, wherein, The processing device is configured to determine that the maximum transmit power at which the wireless device, based on the identified parameter value and across a range of values of each of the other parameters, has an associated transmit metric that meets the one or more target transmit metrics includes: The processing device is further configured to: Determine the updated power as the maximum transmit power for which, for the identified parameter value and the range of variation of each of the other parameters, the associated SM and EVM do not exceed the maximum EVM and the target SM, respectively.

21. The wireless device according to claim 20, wherein, The SM and the EVM associated with the maximum transmit power do not exceed the maximum EVM and the target SM by one or more tolerance values, respectively.

22. The wireless device according to claim 15, wherein, The processing device is configured to determine an updated transmit power based on the identified parameter value and the range of values of each of any other parameters includes: The processing device is further configured to: Determine the updated transmit power according to a multidimensional array of incremental transmit powers corresponding to the range of values of each of the plurality of parameters of the wireless device, wherein the incremental transmit power corresponding to each combination of values of the plurality of parameters is characterized such that the transmit metric associated with the transmit power meets the one or more target transmit metrics.

23. The wireless device according to claim 22, wherein, The multidimensional array is constructed according to the plurality of parameters of the wireless device, wherein the plurality of parameters includes the data rate and transmit mode of the wireless device.

24. The wireless device according to claim 23, wherein, The plurality of parameters in the multidimensional array further includes the operating frequency and operating bandwidth of the wireless device.

25. The wireless device according to claim 22, wherein, The incremental transmit power corresponding to each combination of variations of the plurality of parameters in the multidimensional array is characterized relative to the initial transmit power.

26. The wireless device according to claim 25, wherein, The initial transmit power corresponds to the nominal values of the plurality of parameters, and wherein, when the plurality of parameters of the wireless device are at the nominal values, the initial transmit power enables the associated transmit metric to meet the one or more target transmit metrics.

27. The wireless device according to claim 22, wherein, The processing device is configured to determine the updated transmit power according to the multidimensional array of incremental transmit powers includes: The processing device is further configured to: Determine the minimum value of the incremental transmit power corresponding to the identified parameter value and across the range of variation of each of the other parameters as the updated transmit power.

28. The wireless device according to claim 15, wherein, The processing device is configured to identify the value of each of one or more parameters among the plurality of parameters of the wireless device includes: The processing device is further configured to: Periodically identify the value of each of the one or more parameters, And wherein, the processing device is configured to determine an updated transmit power based on the identified parameter value and the range of values of each of any other parameters includes: The processing device is further configured to: Periodically determine the updated transmit power based on the periodically identified one or more identified parameter values and the range of values of each of any other parameters among the other parameters.

29. The wireless device according to claim 15, wherein, The wireless device includes a wireless local area network (WLAN) device.

30. A wireless communication device, comprising: one or more antennas configured to transmit or receive over a wireless channel; a processing device configured to: initialize the transmit power of the wireless communication device to an initial transmit power, the transmit power being associated with one or more transmit metrics; identify the value of each of one or more of a plurality of parameters of the wireless communication device; determine an updated transmit power based on the identified parameter values of the plurality of parameters and the range of values of each of any other parameters, the updated power being determined as the maximum transmit power at which the associated transmit metric satisfies one or more target transmit metrics when the wireless communication device transmits based on the identified parameter values and across the range of values of each of the other parameters, wherein each other parameter corresponds to a parameter for which the value associated with the wireless communication device respectively cannot be identified by the wireless communication device; and adjust the transmit power based on the updated transmit power.

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