Devices that reduce errors in unused tones in partial bandwidth wireless transmission systems

Abstract

A means for reducing errors in unused tones in a partial bandwidth wireless transmission system is provided. In one embodiment, the means includes: a compensation circuit for selecting one of a plurality of compensation sets based on an allocated resource unit (RU) and using the selected compensation set to compensate a digital complex signal; a digital-to-analog converter for converting the compensated digital complex signal into a compensated analog complex signal; a mixer coupled to the digital-to-analog converter for up-converting the compensated analog complex signal into a radio frequency (RF) signal; and a power amplifier coupled to the mixer for amplifying the RF signal.

Description

Background Technology

[0001] As more and more devices, including Internet of Things (IoT) devices, communicate wirelessly in homes and other wireless local area networks (WLANs), the number of participants and their bandwidth continue to rise.

[0002] One solution for allowing multiple devices to communicate with an access point is Orthogonal Frequency Division Multiple Access (OFDMA), for example, according to the Wi-Fi-6 protocol. Using this technology, an access point can allocate a portion of its bandwidth to different devices, where the amount of bandwidth allocated to each device is called a Resource Unit (RU). Each Resource Unit has a given location within the total bandwidth allocation and is given multiple subcarriers from the total available subcarriers, also called tones. Therefore, RU allocation is for a given location and number of tones. One problem with this system is the so-called unused tone error, in which, for example due to IQ mismatch within the transmitter's circuitry, the transmitter transmits unwanted interference within its unused tones, which may interfere with the allocated RUs of other devices. Summary of the Invention

[0003] In one aspect, an apparatus includes: a compensation circuit for selecting one of a plurality of compensation sets based on resource units (RUs) allocated to the apparatus, and using the selected compensation set to compensate a digital complex signal; a digital-to-analog converter for converting the compensated digital complex signal into a compensated analog complex signal; a mixer coupled to the digital-to-analog converter for up-converting the compensated analog complex signal into a radio frequency (RF) signal; and a power amplifier coupled to the mixer for amplifying the RF signal.

[0004] In one example, the device further includes a storage device for storing the plurality of compensation sets. The storage device may include non-volatile memory written during the manufacture of the device. The device may be an integrated circuit having compensation circuitry and non-volatile memory. The non-volatile memory may store the plurality of compensation sets, including: a default compensation set; a first set of compensation sets for a first plurality of RUs, each of the first plurality of RUs having N tones; and a second set of compensation sets for a second plurality of RUs, each of the second plurality of RUs having M tones.

[0005] In one example, the compensation circuit may further include a selection circuit for selecting one of the plurality of compensation sets based on the RUs assigned to the device. The selection circuit may select a common compensation set from the first set of compensation sets for a first RU and at least one adjacent RU. The selection circuit may select a default compensation set for a first portion of uplink packet communication and select one of the first set of compensation sets for a second portion of uplink packet communication. When the selection circuit has not yet received RU allocation information, it may select the default compensation set for the first portion of uplink packet communication. The compensation circuit may include a selection circuit for selecting one of the plurality of compensation sets at least in part based on at least one of the location and size of the RU. The compensation circuit may include a complex multiplier for multiplying a digital complex signal with the selected compensation set, which includes complex values. The RU may be a first portion of bandwidth having multiple tones, i.e., a first portion of bandwidth of a partial bandwidth network, wherein the compensation circuit is used to reduce unused tone errors in one or more other portions of bandwidth of the partial bandwidth network.

[0006] In another aspect, a method includes: for each of a plurality of RUs in a partial bandwidth network, iteratively performing the following operations: in a device under test having an integrated circuit including a transmitter, generating a test signal for one of the plurality of RUs in the partial bandwidth network; for each of a plurality of candidate compensation sets, iteratively performing the following operations: in the device under test, compensating the test signal using the candidate compensation set; transmitting the compensated test signal from the device under test; and for the other RUs in the partial bandwidth network, measuring and recording unused tone error information associated with the compensated test signal; determining an optimal compensation set for that RU based at least in part on the unused tone error information; and storing the optimal compensation sets for at least some of the plurality of RUs in a storage device.

[0007] In one example, the method further includes programming the integrated circuit using a stored optimal compensation set for at least some of the plurality of RUs. Programming the integrated circuit includes storing a plurality of entries into the non-volatile memory of the integrated circuit, each entry including a compensation set and an identifier of one or more RUs to use the compensation set. The method may further include determining an optimal compensation set for two or more of the plurality of RUs. The method may further include determining an optimal compensation set when a first optimal compensation set for a first RU is within at least a threshold distance of a second optimal compensation set for a second RU.

[0008] In another aspect, a system includes a transmitter. The transmitter may include: a digital baseband processor for receiving information to be transmitted and processing the information into packets having a preamble and a payload, the packets being formed from complex signals; a storage device for storing a plurality of compensation sets, each of the plurality of compensation sets being associated with at least one RU of a partial bandwidth wireless system; a selection circuit coupled to the storage device, wherein the selection circuit is configured to select a compensation set from the plurality of compensation sets, at least in part based on the RUs assigned to the transmitter; and a compensation circuit coupled to the selection circuit, wherein a calculation circuit is configured to compensate the complex signals for IQ mismatch of the transmitter based on the selected compensation set.

[0009] In one example, the compensation circuit includes a complex multiplier for multiplying a complex signal by a selected compensation set, which includes complex values.

[0010] In one example: in a first mode, the selection circuit statically selects a compensation set to compensate for the complex signal of the packet; and in a second mode, the selection circuit dynamically selects a first compensation set and a second compensation set to compensate for the complex signal of the packet. When the transmitter is assigned a first RU or at least one adjacent RU, the selection circuit can select a common compensation set from the plurality of compensation sets. Attached Figure Description

[0011] Figure 1 It is a graphical representation of the transmission of physical protocol data units based on triggers.

[0012] Figure 2 This is a block diagram of a transmitter according to one embodiment.

[0013] Figure 3 This is a flowchart of a method according to one embodiment.

[0014] Figure 4 This is a flowchart of a calibration technique according to one embodiment.

[0015] Figure 5 This is a block diagram of packet transmission in a partial bandwidth network and compensation set application according to one embodiment.

[0016] Figure 6 This is a block diagram of a representative integrated circuit incorporated in one embodiment.

[0017] Figure 7 This is a high-level diagram of a network according to one embodiment. Detailed Implementation

[0018] In various embodiments, a transmitter operating in a partial bandwidth wireless network can be configured to dynamically select one of a plurality of compensation sets for performing IQ imbalance compensation during transmission operations. In this way, the transmitter can transmit within its assigned RU with reduced interference in other RUs (and particularly in RUs including mirror frequencies to the assigned RU).

[0019] To illustrate the error of unused sounds, please refer to [reference]. Figure 1 , Figure 1 This is a graphical illustration of a transmission based on triggered Physical Protocol Data Units (TB PPDUs), where the transmitter is assigned one of multiple such RUs in a partial bandwidth system.

[0020] Specifically, the total bandwidth 110 of wireless network 100 is... Figure 1 As shown in the figure. In one embodiment, the total bandwidth 110 may be 20 MHz. The center or DC frequency 120 exists in the middle portion of the total bandwidth 110. As further shown, the transmission spectrum of the first RU 130 is illustrated. It is assumed that the first transmitter is transmitting at this first RU location. As an example, this first RU location may be for a 26-tone RU. Although the transmitter transmits the first RU 130 at a relatively high power, there is a slightly high unused tone error at the mirror frequency 140 due to mismatches or other nonlinearities within the transmitter, even when using a single default compensation value. Depending on the power levels of these mirror frequency components, an undesirable high level of interference may occur for another transmitter transmitting at the RU location at the mirror frequency 140.

[0021] IQ imbalance is one of the impairments observed in radio frequency (RF) systems and arises from gain / phase mismatch between in-phase and quadrature paths. IQ imbalance causes spurious emissions (frequency-dependent) at mirror frequency locations. Typically, IQ imbalance can be measured during the calibration process, and compensation techniques are used to mitigate its effects. In a full-bandwidth WLAN system, a single tone is transmitted at a distance of several MHz from the carrier, and a range of compensation values ​​is swept, with spurious emissions measured for each compensation value. The set of compensation values ​​with the lowest spurious emissions selected for use is shown.

[0022] As discussed, in partial bandwidth systems (e.g., those used in Wi-Fi-6 or Long Term Evolution (LTE) systems), each station transmits within its assigned RU by the access point. In the presence of IQ imbalance, transmissions in an RU cause spurious emissions in the mirror frequency (unused tone) corresponding to that RU. These spurious emissions in the unused tone act as interference to other stations and are required to be within limits specified in a given standard (such as the IEEE 802.11ax (Wi-Fi-6) standard). The unused tone error metric is calculated based on the power of unused subcarriers within a certain range and the power of subcarriers in occupied RUs. The unused tone error requirement is defined over a 26-tone area spanning both sides of the RU across the entire supported bandwidth. This requirement is relaxed for the 26-tone group adjacent to the occupied RU compared to the 26-tone group farther from the adjacent RU.

[0023] As mentioned above Figure 1 The single default compensation set discussed, assuming a full bandwidth scenario, may not be suitable for partial bandwidth transmissions because spurious emissions can lead to violations of unused tone error requirements. Embodiments providing multiple compensation sets can be used to achieve low spurious emissions (RU location and size) for all partial bandwidth transmissions. Therefore, in the case of the embodiments, unused tone errors, particularly those at mirror frequencies, can be reduced by providing compensation. As will be described, this compensation can be performed using a specific compensation set that is superior for that partial transmission to a single default compensation value that can be used in a full bandwidth transmission implementation.

[0024] Now for reference Figure 2 A block diagram of a transmitter according to one embodiment is shown. Figure 2 As shown in the high-level diagram, transmitter 200 includes various circuit modules to process message information, encapsulate it for transmission, and transmit it. In the high-level diagram, the message information to be transmitted is provided to modulator 210. Although embodiments are not limited in this respect, in the use cases herein, modulator 210 can be configured to implement a modulation scheme suitable for OFDMA. For example, modulation can be based on orthogonal frequency division multiplexing (OFDM) with binary phase shift keying (BPSK) symbols. Other digital modulation schemes may include quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (QAM), 64-QAM, or 256-QAM. The modulation process may include channel coding, interleaving, cyclic redundancy check (CRC) padding, constellation mapping, inverse fast Fourier transform (IFFT) / fast Fourier transform (FFT) operations, etc.

[0025] The modulated information is then transmitted to a digital baseband processor 220, which can perform various baseband processing operations, including upscaling, scaling, clipping, and filtering. Furthermore, the digital baseband processor 220 can generate complex signals from the incoming modulated information, namely the IQ signals provided to the IQ compensation circuit 230. Although in Figure 2 While shown as separate circuitry in a high-level view, it is to be understood that in some implementations, the compensation circuitry 230 may be included within the baseband processor 220. In some implementations, the digital baseband processor 220 may be a standalone processor or may be implemented within a digital signal processor (DSP). It is to be understood that in some embodiments, some or all of the compensation circuitry 230 may be implemented as a hardware circuit module configured to execute instructions stored in a non-volatile memory device or other non-transitory storage medium to select an appropriate compensation value and perform the compensation described herein.

[0026] As shown, the IQ compensation circuit 230 includes a compensation storage device 232 capable of storing multiple compensation sets. Depending on the implementation, different numbers of compensation sets can be stored, including a default compensation set and other groups or subsets of compensation sets that can be used for different combinations of RU locations and sizes. The compensation storage device 232 can be implemented as a memory, register, etc. In some use cases, the storage device 232 can be implemented as a non-volatile memory that has multiple compensation sets written to it during manufacturing. As further described herein, these multiple compensation sets can be determined during the calibration process. In other cases, the compensation sets can be included in firmware stored in non-volatile memory, or exist within or coupled to the transmitter 200, such that these values ​​are stored in the compensation storage device 232 upon initialization.

[0027] In one particular embodiment, the compensation storage device 232 can store 15 IQ imbalance compensation sets, from which one can be selected based on the RUs used for transmission. In this embodiment, a compensation set is a default set (e.g., for 242-tone RUs or the full bandwidth case) or an RU occupying all tones. The default set can also be used when RU allocation information is unavailable. The compensation storage device 232 can also store eight sets corresponding to eight 26-tone RUs (where the middle RU can use the default set). The compensation storage device 232 can also store four sets corresponding to four 52-tone RUs and two sets corresponding to two 106-tone RUs.

[0028] Referring again to compensation circuit 230, selection circuit 235 is coupled to compensation storage device 232. In one embodiment, selection circuit 235 may be implemented as a multiplexer. A given set of compensations within compensation storage device 232 may be selected for a given transmission based on RU information. Note that this RU information may originate from a higher layer, such as the MAC of transmitter 200 or other upper layers, in response to an RU allocation message received from the access point. In one embodiment, this RU information may take the form of RU location and size information.

[0029] Selection circuit 235 can select a given compensation set based at least in part on the RU information. As shown, the selected compensation set is provided to complex multiplier 240, which can perform complex multiplication between the compensation set and the incoming IQ signal. It should be understood that this complex multiplication can therefore compensate the IQ signal to accommodate IQ mismatch and / or other nonlinearities of transmitter 200. The resulting compensated IQ signal is provided to analog baseband processor 250, which can perform further baseband processing, such as converting the digital IQ signal to an analog IQ signal (e.g., via an included digital-to-analog converter), low-pass filtering, etc.

[0030] The resulting signal is then provided to a complex mixer 260, which upconverts the signal to a radio frequency (RF) level based on the mixing signal received from the clock generator 270. These RF signals can then be amplified in a power amplifier 280 and transmitted via an antenna 290. It is to be understood that in Figure 2 In this embodiment, all circuit modules except antenna 290 can be implemented on a single integrated circuit (such as a given IoT IC). Although... Figure 2 This high-level illustration is shown in the embodiments, but it is to be understood that many variations and alternatives are possible.

[0031] Now for reference Figure 3 A flowchart of a method according to one embodiment is shown. Figure 3 As shown, method 300 is a compensation method executed within the transmitter. Accordingly, method 300 can be executed independently by a hardware circuit module within the transmitter and / or further executed using firmware and / or software.

[0032] As illustrated, method 300 begins by receiving an RU allocation message (box 310) from an access point. This RU allocation message can be sent from the access point within a given network to allocate a portion of the total bandwidth of the wireless network to a transmitter. While the allocation message may include various information, location and size information are of particular interest here. That is, the location information indicates which of a plurality of RU locations the transmitter has been allocated to, and the size indicates the number of tones allocated for the RU. It should be understood that this information can be obtained from RU allocation messages received within a given device or station that, in addition to having a transmitter, also has a receiver, for example, implemented as a separate circuit module or combined as a transceiver. It should be noted that the processing of this RU allocation message can occur at higher layers (such as the MAC layer), and therefore some delay may occur before the physical layer circuit module receives the indication of the RU allocation message.

[0033] Control is then passed to box 320, where a compensation set can be selected based on the location and size of the active RU. In one embodiment, the selection circuit module can select an appropriate compensation set from a plurality of such compensation sets based on the indicated location and size. It should be noted that if the RU location and size information is not yet available at the beginning of a transmission period, for example due to the delay described above, a default compensation set can initially be selected for use at box 320. It should be understood that during a given packet transmission, when the RU location and size information becomes available, this default set can be updated to the selected compensation set.

[0034] Still referencing Figure 3 The control is then passed to block 330, where a selected compensation set can be used to compensate uplink packets, such as TB PPDU packets. As discussed above, in one embodiment, compensation can be achieved by processing the incoming IQ signal with a compensation value. In one embodiment, this processing can be a complex multiplication between the incoming IQ signal to be transmitted and the selected compensation set, which is itself a complex number. This compensation can be performed in compensation circuitry (e.g., IQ compensation circuitry). The compensated uplink packets can then be transmitted (block 340). It should be noted that various signal processing can be performed on the compensated IQ signal to provide gain control, conversion to analog form, etc. Furthermore, the signal can be up-converted to RF level before being transmitted via the antenna and then amplified in a power amplifier. It should be understood that, although... Figure 3 This high level is shown in the embodiments, but many variations and alternatives are possible.

[0035] Therefore, in the case of the embodiments, when partial bandwidth transmission occurs, the transmitter can perform compensation using carefully selected compensation values ​​appropriate for the location and size of a given RU. To obtain these carefully selected compensation sets, a calibration process can be performed. In one embodiment, this calibration process can be performed as an offline procedure in a laboratory setting. More specifically, the designer or manufacturer of the integrated circuit can perform the calibration using a manufactured IC implemented in a test environment. The IC can be controlled to transmit test signals to enable the measurement of unused tone errors in order to identify the optimal compensation set for different RUs. The test environment may include the device under test (i.e., a given integrated circuit such as one adapted to an evaluation board, IoT device, etc.), measurement circuitry modules, and test control software (such as a given test suite that can be executed on one or more computing devices in the test environment).

[0036] Now for reference Figure 4 A flowchart of a calibration technique according to one embodiment is shown. Figure 4 As shown, method 400 can be executed in a test environment and can begin by generating a test signal for the selected RU location and size (block 410). For example, the test software can instruct the IC to generate a test signal for a given RU. Next, at block 415, the test signal can be compensated using a candidate compensation set. It should be understood that the candidate compensation set can be random values, such as one from a set of random values ​​(each random value has a given complex value).

[0037] As described above, compensation can be performed via complex multiplication between the test signal and the complex values ​​of the candidate compensation set. After compensation, the compensated test signal is transmitted (box 420), and the transmitted signal can be measured, for example, in a test setup for unused tone errors (box 425). It should be noted that the unused tone error can be measured for each RU across the full bandwidth, such that the unused tone error for each RU (except for the selected RU) can be determined for the entire spectrum against the candidate compensation set. This information can be stored, for example, in a log file for later use.

[0038] Following this process, it can be determined whether additional candidate compensation sets exist (diamond box 430). If so, the process iterates back to box 410. Although the embodiments are not limited in this respect, for performing the calibration process, approximately 64 to 256 candidate compensation sets can be considered. In one embodiment, instead of linearly measuring the performance of all candidate compensation values, a gradient descent method can be used, where the process initially begins with several compensation sets with low resolution, and the resolution is further increased based on the measurement data, and the compensation sets are reduced. Once all candidate compensation sets for a given RU have been tested, and the measurement information has been obtained and recorded, control is passed to diamond box 435 to determine whether there are additional RUs to test. If so, control is again passed back to box 410 for further iterations for all such RUs. Then, when all RUs have been tested for calibration purposes, control is passed from diamond box 435 to box 440.

[0039] At box 440, an optimal compensation set can be determined for each RU location and size. In one embodiment, the recorded information can be analyzed to identify this optimal compensation set for each RU location and size. This optimal set may be one that achieves the minimum unused tone error in the mirror frequencies of the selected RU. In other cases, the optimal compensation set may be a given set that provides the best range of unused tone errors across the entire spectrum.

[0040] In some cases, particularly when the bandwidth of a partial bandwidth system increases, there may be a relatively large number of compensation sets that need to be determined. In such cases, to reduce the complexity and amount of memory required within the transmitter to store all compensation sets, optimizations can be performed to reduce the number of compensation sets. Therefore, at option 450, an attempt can be made to optimize the number of compensation sets.

[0041] This optimization can be performed to attempt to reduce the number of compensation sets that increase with the available bandwidth (e.g., 40 / 80MHz). As discussed above, in one embodiment, there might be 15 compensation sets for 20MHz. For 40MHz, there might be 33 compensation sets. Therefore, optimization can be performed to seek to reduce the number of compensation sets.

[0042] Different considerations can help determine when multiple RUs can use the same compensation set. In one implementation, optimization can be based on differences in the coefficients of different compensation sets. If the compensation set values ​​corresponding to adjacent RUs are similar (e.g., within a threshold distance or range from each other), a single set of compensation values ​​can be used for these RUs (note that two or more RUs can use a common compensation set). In another implementation, optimization can be based on the image suppression ratio (IRR), unused tone error (UTE), and / or any other compliance metric. In this case, if the IRR or UTE constraints are met, the compensation set observed for the larger RU can be used for the smaller RU in the same space.

[0043] For example, 106 tones on the left or right side within a 20MHz bandwidth can accommodate two 52-tone RUs or four 26-tone RUs. The compensation set obtained for the 106-tone RU can be used for 26 / 52-tone RUs in the same frequency region. Similarly, if a compensation set is available for a 26-tone RU, larger RUs can also use it.

[0044] Finally, at box 460, a compensation set can be stored for programming into the transmitter. For example, a table with multiple entries can be generated, where each entry includes a compensation set (i.e., a complex value) and a corresponding RU with a given compensation set, along with a location and size (or multiple locations and sizes). It is understood that, for example, during factory programming, this table can be stored in a given non-transitory storage medium and then programmed into an integrated circuit with non-volatile memory to store the table. It is also possible that such a table can be implemented as part of the integrated circuit's firmware, which can be written into the integrated circuit's memory when the integrated circuit is powered on. In other cases, the compensation values ​​can be dynamically updated in the field, for example, via over-the-air updates of the IC code and / or firmware.

[0045] During field operation, the application of the compensation set corresponding to a given RU can be performed in different ways, depending on when the RU information is received within the IQ compensation circuit module. In some implementations, the application of the compensation set can be performed in an inter-group or static manner, while in other implementations, the compensation set can be applied in an intra-group or dynamic manner.

[0046] Now for reference Figure 5 This shows a block diagram of packet transmission in partial bandwidth networks and compensation set applications. (Example) Figure 5As shown, partial bandwidth network communication 500 includes RU packet transmission 510 with preamble, signal fields, and payload information. More specifically, the preamble is formed by conventional short and long training fields 512, 514 and conventional and repeated conventional signal fields 516, 518. In addition to the preamble, other training and signal fields include 520, 522, and 524. Finally, there is a payload portion 526 containing data. In this embodiment, partial bandwidth transmission occurs from the fields present after HE-SIGA 520.

[0047] exist Figure 5 In the first mode, i.e., the inter-group mode, a single compensation set 530 is selected for the entire duration of the group. This mode can be used when the RU allocation information is known a priori, i.e., available at the beginning of the group.

[0048] In the second mode, i.e., the intra-group mode, different compensation sets are used for different parts of the group. This may occur when RU information is unavailable to the selection circuit at the beginning of the group, or for other reasons. In this example, a default compensation set 540 may be used for the first part of the group, and then a compensation set 545 selected based on the RU information may be used for the second part of the group. The points where the compensation values ​​are changed can be programmable. In one embodiment, an RU-based compensation set may be enabled during the HE portion of the group (where unused tone errors are measured on the HE data portion of the group).

[0049] Now for reference Figure 6 A block diagram of a representative integrated circuit 600, including compensation circuitry as described herein, is shown. Figure 6 In the embodiments shown, the integrated circuit 600 may be, for example, a microcontroller, a wireless transceiver that can operate according to one or more wireless protocols (among others, such as WLAN-OFDM, WLAN-DSSS, Bluetooth), or other devices that can be used in a variety of use cases including sensing, metering, monitoring, embedded applications, communications, applications, etc., and may be particularly suitable for use in IoT devices.

[0050] In the illustrated embodiment, integrated circuit 600 includes memory system 610. In one embodiment, memory system 610 may include non-volatile memory, such as flash memory, and volatile memory devices, such as RAM. In one embodiment, the non-volatile memory may be implemented as a non-transitory storage medium capable of storing instructions and data. Such non-volatile memory may store instructions, including instructions for determining IQ mismatches and compensating for IQ mismatches (and storing multiple compensation sets) as described herein.

[0051] The memory system 610 is coupled to a digital core 620 via a bus 650. The digital core 620 may include one or more cores and / or microcontrollers that act as the main processing unit of the integrated circuit. Furthermore, the digital core 620 may be coupled to a clock generator 630, which may provide one or more phase-locked loops or other clock generator circuits to generate various clocks for use by the circuit modules of the IC.

[0052] As further illustrated, IC 600 further includes a power circuit module 660, which may include one or more voltage regulators. Depending on the specific implementation, additional circuit modules may optionally be present to provide various functionalities and interaction with external devices. Such circuit modules may include: an interface circuit module 660, which can provide interfaces with various off-chip devices; and a sensor circuit module 670, which may include various on-chip sensors, including digital and analog sensors, to sense desired signals, such as for metering applications.

[0053] In addition, such as Figure 6 As shown, transceiver circuit module 680 can be provided to enable the transmission and reception of wireless signals, for example, according to one or more local or wide-area wireless communication schemes such as Zigbee, Bluetooth, IEEE 802.11, IEEE 802.15.4, cellular communication, etc. As shown, transceiver circuit module 680 includes compensation circuitry 685, which can perform compensation using a selected set of compensations to reduce unused tone errors as described herein. It should be understood that although shown in this high-level view, many variations and alternatives are possible.

[0054] It is important to note that ICs such as those described in this article can be implemented in a variety of different devices, such as IoT devices. As two examples, the IoT device could be a smart light bulb in a home or industrial automation network, or a smart utility meter used in a smart utility network, such as a mesh network in which communication is based on the IEEE 802.15.4 specification or other such wireless protocols.

[0055] Now for reference Figure 7 A high-level diagram of a network according to one embodiment is shown. Figure 7 As shown, network 700 includes various devices, including smart devices (such as IoT devices), routers, and remote service providers. Figure 7 In embodiments, the mesh network 705 may exist, for example, in a network with multiple IoT devices 710. 0-nIn the building. This IoT device can perform IQ compensation using a selected compensation set based at least in part on the allocated RUs as described herein. As shown, at least one IoT device 710 is coupled to a router 730, which in turn communicates with a remote service provider 760 via a wide area network 750 (e.g., the Internet). In one embodiment, the remote service provider 760 may be a back-end server of a utility handling communications with the IoT device 710. It should be understood that, although with Figure 7 This high level is shown in the embodiments, but many variations and alternatives are possible.

[0056] While this disclosure has described a limited number of implementations, many modifications and variations will be apparent to those skilled in the art upon which this disclosure is made. The appended claims are intended to cover all such modifications and variations.

Claims

1. An apparatus for reducing errors, comprising: A compensation circuit is used to select one of a plurality of compensation sets as the selected compensation set, and to use the selected compensation set to compensate the digital complex signal. A digital-to-analog converter is used to convert a compensated digital complex signal into a compensated analog complex signal. A mixer coupled to the digital-to-analog converter is used to upconvert a compensated analog complex signal into a radio frequency (RF) signal; as well as A power amplifier coupled to the mixer is used to amplify the RF signal. Before the Resource Unit (RU) allocation information is received, for the first part of the uplink packet communication, a default compensation set from the plurality of compensation sets is selected as the chosen compensation set. After receiving the RU allocation information, for the second part of the uplink packet communication, another compensation set from the plurality of compensation sets is selected as the chosen compensation set. The other compensation sets are based on the RU allocation information. The default compensation set refers to all RUs occupying the bandwidth of the wireless network and is intended for use before RU allocation information has been received.

2. The apparatus of claim 1, further comprising a storage means for storing the plurality of compensation sets.

3. The apparatus of claim 2, wherein the storage device includes a non-volatile memory written during the manufacture of the apparatus, and the apparatus includes an integrated circuit having the compensation circuit and the non-volatile memory.

4. The apparatus of claim 3, wherein the non-volatile memory is used to store the plurality of compensation sets, comprising: Default compensation set; The first set of compensations is used for the first plurality of RUs, each of which has N tones; as well as The second set of compensation is used for the second plurality of RUs, each of which has M tones.

5. The apparatus of claim 4, wherein the compensation circuit further comprises a selection circuit for selecting the selected compensation set.

6. The apparatus of claim 5, wherein the selection circuit is configured to select a common compensation set from a first set of compensation sets for the first RU and at least one adjacent RU.

7. The apparatus of claim 1, wherein the compensation circuit includes a selection circuit for selecting one of the plurality of compensation sets based at least in part on at least one of the positions and sizes of the RUs.

8. The apparatus of claim 1, wherein the compensation circuit includes a complex multiplier for multiplying the digital complex signal with a selected compensation set, the selected compensation set including complex values.

9. The apparatus of claim 1, wherein the RU includes a first portion bandwidth having a plurality of tones, i.e., a first portion bandwidth of a partial bandwidth network, wherein the compensation circuitry is used to reduce unused tone errors in one or more other portion bandwidths of the partial bandwidth network.

10. A system for reducing errors, comprising: Transmitter, including: A digital baseband processor is used to receive information to be transmitted and process the information into packets with preambles and payloads, the packets being formed from complex signals; A storage device for storing a plurality of compensation sets, each of the plurality of compensation sets being associated with at least one resource unit (RU) of a partial bandwidth wireless system; A selection circuit coupled to the storage device is used to select a compensation set from the plurality of compensation sets; and A compensation circuit coupled to the selection circuit, wherein the compensation circuit is used to compensate the complex signal for IQ mismatch of the transmitter according to the selected compensation set; In the first mode, the selection circuit is used to statically select a static compensation set based on the RUs allocated to the transmitter to compensate the complex signals of the packet, and each complex signal of the packet is multiplied by the static compensation set; and In the second mode, the selection circuit is configured to dynamically select a first compensation set during the first portion of the packet, the first compensation set being a default compensation set and each complex signal in the first portion of the packet being multiplied by the first compensation set, and the selection circuit is configured to select a second compensation set to compensate for the complex signals in the second portion of the packet in response to receiving an RU allocation message from the access point and at least in part based on the RUs allocated to the transmitter for the second portion of the packet received from the access point, and each complex signal in the second portion of the packet being multiplied by the second compensation set.

11. The system of claim 10, wherein the compensation circuit includes a complex multiplier for multiplying the complex signals of the group.

12. The system of claim 10, wherein when the transmitter is assigned a first RU or at least one adjacent RU, the selection circuit is used to select a common compensation set among the plurality of compensation sets.

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