Gain control for optimizing sensitivity and blocking performance

Abstract

The name of the invention is gain control for optimizing sensitivity and blocking performance. In one embodiment, a method includes setting, via a controller of a receiver, a plurality of gain components of the receiver for maximum gain setting for an automatic gain control (AGC) sensitivity (SENS) mode; receiving, in a controller of the receiver, an indication that a power level of an intermediate frequency (IF) signal measured at an output of an IF amplifier of the receiver exceeds a first threshold; and transitioning from an AGC SENS mode to an AGC adjacent channel interference (ACI) mode in response to an indication that the power level of the IF signal exceeds a first threshold.

Description

Background Art

[0001] In a radio receiver, a radio frequency (RF) signal is received via an antenna. The signal is then processed in the signal processing path of the receiver. General receiving operations include amplification, down-conversion, filtering, and digitization, resulting in a digitized signal that can then be processed digitally (such as demodulation for a particular modulation technique).

[0002] Many receivers include multiple amplifiers or other gain components. At least some of these gain components can be controlled. Although many gain control techniques are known, such techniques may suffer from various drawbacks, including complexity and processing difficulty. One such complexity is that for some wireless protocols, such as certain Wi-Fi (e.g., IEEE 802.11) protocols, there is a trade-off between sensitivity and blocking performance across different modulation and coding schemes (MCS) conditions. That is, across different MCS conditions and bandwidths, the sensitivity and blocking conditions overlap, and it is generally not possible to optimize the receiver across MCS conditions and bandwidths because these conditions and bandwidths may change in real time. Summary of the Invention

[0003] In one aspect, a receiver includes: a low-noise amplifier (LNA) for receiving and amplifying a radio frequency (RF) signal; a mixer for down-converting the RF signal to an intermediate frequency (IF) signal; a programmable gain amplifier (PGA) coupled to the mixer to amplify the IF signal, the LNA, mixer, and PGA having a first controllable gain; a filter coupled to the PGA to filter the amplified IF signal, the filter having a second controllable gain; a digitizer coupled to the filter to digitize the filtered IF signal into a digitized signal; a first power detector coupled to the input of the LNA, the first power detector for outputting a first detection signal in response to the RF signal exceeding a first threshold; a second power detector coupled to the output of the PGA, the second power detector for outputting a second detection signal in response to the IF signal exceeding a second threshold; and a controller for transitioning from an automatic gain control (AGC) sensitivity (SENS) mode to an AGC adjacent channel interference (ACI) mode in response to the second detection signal.

[0004] In one implementation, in the AGC ACI mode, the controller first backs off the second controllable gain and then backs off the first controllable gain thereafter. The receiver may further include at least one RF gain component coupled to the input of the LNA, the at least one RF gain component having a third controllable gain, wherein after the first controllable gain is backed off, the controller backs off the third controllable gain. The controller may then remove the third controllable gain and further adjust the first controllable gain if the signal metric information exceeds a third threshold. In the AGC SENS mode, the controller first backs off the second controllable gain and then backs off the first controllable gain thereafter.

[0005] In one implementation, in response to a first detection signal, the controller directly backs off the gain of at least one RF gain component. In response to the first detection signal, the controller directly backs off the gain of the at least one RF gain component until the first detection signal indicates that the RF signal is less than a first threshold.

[0006] In one implementation: in the AGC SENS mode, the controller optimizes the receiver for noise performance; and in the AGC ACI mode, the controller optimizes the receiver for linearity and headroom. In the AGC SENS mode, the controller causes a maximum RF gain setting for at least the LNA. Also, in the AGC SENS mode, the controller causes a maximum RF gain setting for at least the LNA unless a blocker signal is detected. The receiver may further include a plurality of gain tables, wherein at least one first gain table is associated with the AGC SENS mode and at least one second gain table is associated with the AGC ACI mode.

[0007] In another aspect, a method includes: setting, via a controller of a receiver, a plurality of gain components of the receiver for a maximum gain setting in the AGC SENS mode; receiving, in the controller of the receiver, an indication that a power level of an IF signal measured at an output of an IF amplifier of the receiver exceeds a first threshold, the IF signal originating from an RF signal received in the receiver; and transitioning from the AGC SENS mode to the AGC ACI mode in response to the indication that the power level of the IF signal exceeds the first threshold.

[0008] In one implementation, the method may further include dynamically adjusting a gain setting for one or more of the plurality of gain components for the receiver based on a received signal strength indication obtained from a digital processor of the receiver. This dynamic adjustment of the gain setting for one or more of the plurality of gain components may include: for the AGC SENS mode, dynamically adjusting the gain setting for one or more of the plurality of gain components in a first order; and for the AGC ACI mode, dynamically adjusting the gain setting for one or more of the plurality of gain components in a second order.

[0009] In one or more implementations, the method may further include: in response to an indication that the power level of the IF signal exceeds a first threshold, adjusting a gain setting of a filter of the receiver, the filter being coupled to an output of the IF amplifier. The method may further include: receiving, in a controller of the receiver, an indication that the power level of the RF signal exceeds a second threshold; and in response to the indication that the power level of the RF signal exceeds the second threshold, dynamically adjusting a gain setting for at least one RF gain component of the receiver. Further, the method may include: optimizing the receiver for noise performance in the AGC SENS mode; and optimizing the receiver for linearity in the AGC ACI mode.

[0010] In yet another aspect, a wireless device includes: an antenna configured to transmit a transmitted RF signal and to receive a received RF signal; and an integrated circuit (IC) coupled to the antenna.

[0011] The IC may include: an attenuator controllable to attenuate the received RF signal, the attenuator including a first gain control region; an LNA coupled to the attenuator to receive and amplify the received RF signal; a mixer configured to down-convert the received RF signal to an IF signal; an IF amplifier coupled to the mixer to amplify the IF signal, the LNA, mixer, and IF amplifier including a second gain control region; a filter coupled to the IF amplifier to filter the amplified IF signal, the filter including a third gain control region; a digitizer coupled to the filter to digitize the filtered IF signal into a digital signal; and a digital signal processor (DSP) coupled to the digitizer, the DSP being configured to process the digital signal; and a controller configured to transition from the AGC SENS mode to the AGC ACI mode in response to a second detection signal.

[0012] The wireless device further includes: a first power detector coupled to the output of the attenuator, the first power detector for outputting a first detection signal in response to the received RF signal output from the attenuator exceeding a first threshold; and a second power detector coupled to the output of the IF amplifier, the second power detector for outputting a second detection signal in response to the amplified IF signal exceeding a second threshold.

[0013] In one implementation, the wireless device further includes a storage device to store a plurality of gain tables, wherein at least one first gain table is associated with the AGC SENS mode, and at least one second gain table is associated with the AGC ACI mode.

[0014] In one implementation, the controller is to dynamically adjust a first gain control region, a second gain control region, and a third gain control region in a first order for the AGC SENS mode; and dynamically adjust the first gain control region, the second gain control region, and the third gain control region in a second order for the AGC ACI mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram of a receiver according to one embodiment.

[0016] Figure 2 is a flowchart of a method according to one embodiment.

[0017] Figure 3A is a graphical illustration of a gain lineup for an automatic gain control (AGC) sensitivity (SENS) mode according to one embodiment.

[0018] Figure 3B is a graphical illustration of a gain lineup for the AGC adjacent channel interference (ACI) mode according to one embodiment.

[0019] Figure 3C is a graphical illustration of the signal levels of processing signals at different points in the receiver processing path relative to the signal level of the incoming RF signal during operation in the AGC SENS mode according to one embodiment.

[0020] Figure 3D is a graphical illustration of the signal levels of processing signals at different points in the receiver processing path relative to the signal level of the incoming RF signal during operation in the AGC ACI mode according to one embodiment.

[0021] Figure 4 is a block diagram of a typical integrated circuit in conjunction with one embodiment.

[0022] Figure 5 is a high-level diagram of a network according to one embodiment. DETAILED DESCRIPTION

[0023] In various embodiments, a receiver is provided with techniques for performing automatic gain control (AGC) operations in a manner that dynamically adapts to changes in receiver operation (e.g., MCS changes) via dynamic changes in AGC modes. To this end, the receiver can be configured to operate in at least one of a dynamically selectable set of at least two AGC modes. In this document, the discussion assumes two modes, referred to as: (1) a sensitivity (SENS) mode; and (2) an adjacent channel interference (ACI) mode. Details of these modes are discussed below. At a high level, it suffices to say that gain control operations occur differently in these different modes. At a minimum, different gain settings are provided for the control of various gain components of the receiver signal processing path. Also, in some cases, different gain components can be enabled / disabled in different modes, and further, it is possible to control the order of gain updates to individual gain components differently.

[0024] Embodiments can at least partially be based on power detectors adapted at specific locations throughout the receiver signal processing path to quickly identify channel conditions that trigger these mode changes. More specifically, embodiments include power detectors operating at radio frequency (RF) level and at intermediate frequency (IF) level. A controller is configured to receive information from these power detectors and dynamically change the AGC mode and cause a dynamic update of the gain settings of one or more gain components at least partially based on this information.

[0025] These rapid updates to the gain settings of various gain components occur such that information being communicated is not lost. More specifically, embodiments can be used in receivers for a variety of packet-based communication protocols where AGC component updates can occur within the preamble portion of packet communication, such that the gain settings can be updated and finalized prior to the communication of the actual payload data of the packet. As an example, packet-based protocols such as Wi-Fi, Bluetooth TM , Zigbee TM and many other Internet of Things (IoT) protocols can leverage embodiments. Embodiments may be applicable to receivers for both constant amplitude modulated signals such as frequency shift keying (FSK), Gaussian frequency shift keying (GFSK), minimum shift keying (MSK) and most other sub-gigahertz (GHz) IoT standards and non-constant amplitude modulated signals such as OFDM.

[0026] As discussed, across different MCS conditions and bandwidths (where the device communicates according to different wireless communication protocols), the sensitivity and blocking conditions overlap. Sensitivity refers to the minimum signal level for a successfully received incoming and desired RF signal. Blocking refers to the situation where an undesired signal (if it is a signal on a channel relatively close to the channel of the desired signal) can adversely affect the correct reception of the desired signal. Embodiments can dynamically trade off between sensitivity and blocking performance to optimize the receiver across MCS conditions and bandwidths. As communication occurs over the air, these MCS conditions and bandwidths can change in real time.

[0027] More specifically, due to the overlapping ranges across different MCS conditions, for various wireless communication protocols such as IEEE 802.11 a / b / g / n / ax (at various bandwidths, e.g., 20 / 40 / 80 MHz bandwidths), embodiments can reliably trade off between sensitivity and blocking performance. In another way, as shown in Tables 1 and 2 below, as the environment and operation change, there is an overlap between the sensitivity and ACI conditions. Depending on the operating situation, sensitivity benefits from the AGC SENS mode, and blocking benefits from the ACI AGC mode (for nulling and linearity).

[0028] Referring to Table 1, shown is the overlap of the SENS and ACI conditions for IEEE 802.11 b / g / n / ax operating at 2.4 GHz and 20 MHz. As shown in Table 1, there is a range of conditions for which the AGC toggles (e.g., switches) between the AGC SENS and AGC ACI modes. Table 1 SI.No. Mode Demod Condition RFIn(dBm) AGC 1 11b 11b 1Mbps -100 SENS 2 11g / n / ax OFDM MCS0 -94 SENS 3 11b 11b 11Mbps -90 SENS 4 11g / n / ax OFDM MCS4 -84 SENS 5 11g / n / ax OFDM MCS0 -79 ACI 6 11g / n / ax OFDM MCS7 -76 SENS 7 11b 11b 1Mbps -74 ACI 8 11g / n / ax OFDM MCS9 -70 SENS 9 11b 11b 11Mbps -70 ACI 10 11g / n / ax OFDM MCS4 -67 ACI 11 11g / n / ax OFDM MCS7 -61 ACI 12 11g / n / ax OFDM MCS9 -54 ACI

[0029] Referring to Table 2, shown is the overlap of the SENS and ACI conditions for IEEE 802.11 a / n / ax operating at 5 GHz and 20 / 40 / 80 MHz. Table 2

[0030] As shown in these tables, for the 20 MHz case, the IEEE 802.11 n / ax MCS7 sensitivity overlaps with the blocking conditions for MCS0 - 4; and the IEEE 802.11 n / ax MSC9 sensitivity overlaps with the blocking conditions for IEEE 802.11b (1 Mbps and 11 Mbps). Thus, for the IEEE 802.11 b / g / n / ax - 20 MHz mode, the sensitivity - ACI trade - off is tightly coupled.

[0031] Generally, sensitivity requires optimal noise performance and maximum RF gain (for a receiver). At and above the reference sensitivity level (where typical blocking tests for ACI, Alternate Adjacent Channel Interference (AACI), and Out-of-Band (OOB) blocking are defined), the receiver needs to be configured for optimal linearity and headroom performance, with optimal RF gain.

[0032] For IEEE802.11ax, the issue of headroom (defined as the maximum signal at the output of a given receiver block before clipping occurs) is exacerbated. In lower process nodes with lower supply voltages, there is a reduction in the dynamic range at the output of the RF portion of the signal processing path. Also, for IEEE 802.11ax, due to the increased number of subcarriers, the Peak-to-Average Power Ratio (PAPR) is higher, and as compared to IEEE 802.11a / b / g / n, there is lower RF filtering since adjacent channel subcarriers are closer to the band edge. All of the above factors can result in a reduction in the dynamic range at the output of this RF path. Thus, the maximum RF gain for the receiver in sensitivity will affect the available headroom for blockers and limit the blocking performance.

[0033] Additionally, the linearity requirement for the IEEE802.11b - 11Mbps data rate is a driver consideration for the Input Third-Order Intercept Point (IIP3), which requires a higher IIP3 (compared to other IEEE802.11 a / g / n / ax modes). For example, in a first scenario, the IIP3 requirement can be -6dBm, and in a second scenario, the IIP3 requirement may be 5dB lower, at -11dBm. Also, using knowledge of IEEE 802.11b for OFDM (802.11a / g / n / ax) information, an appropriate gain table can achieve the IIP3 required under reference sensitivity conditions without overdesigning the receiver for a higher IIP3 to obtain optimal noise and linearity performance.

[0034] Now referring Figure 1 to, a block diagram of a receiver according to an embodiment is shown. As Figure 1As shown in the figure, the receiver 100 is a radio receiver that can be applicable to any type of wireless device. In various embodiments, the input node 105 (which can be an input pin of an integrated circuit (IC) containing the receiver) receives the incoming RF signal (RX_In) from the antenna 103. As can be seen, the RF signal is provided to the attenuator 110. In one embodiment, the attenuator 110 can be implemented as a passive gain network, for example, comprising an inductor (L) and capacitances (C1) and resistances (R1) coupled in parallel. In different embodiments, one or more of these RLC components can be dynamically controlled to control the amount of attenuation, such that the attenuator 110 is regarded as one of the gain components of the receiver 100, namely, the first gain control region 112 of the receiver 100. Although the embodiments are not limited in this regard, in one particular embodiment, the attenuator 110 can provide a controllable gain of -15 dB to 9 dB (e.g., with a 2 dB step per update). In one embodiment, the resistance R1 can be dynamically controlled to adjust the gain setting of the first gain control region 112. Note that in high input conditions, the first gain control region 112 can also be employed in the SENS mode.

[0035] After any attenuation in the attenuator 110, the RF signal is provided to a low noise amplifier (LNA) 120, which (depending on the implementation) can be a current mode low noise transconductance amplifier (LNTA) or a voltage mode LNA. As used herein, unless otherwise specifically stated, the terms "low noise amplifier" and "LNA" cover both current mode LNTAs and voltage mode LNAs. After amplification in the LNA 120, the RF signal is provided to the mixer 125. In various embodiments, the mixer 125 down-converts the RF signal into an IF signal. From there, the IF signal is provided to a programmable gain amplifier (PGA), which is implemented as a transimpedance amplifier (TIA) 131 in Figure 1 an embodiment, formed by an amplifier 130 and a feedback filter (e.g., a first-order filtering function) formed by a capacitor C2 and a resistor R2. The TIA 131 operates to convert the mixer IF current into a voltage signal. In other implementations, the PGA can be implemented as a voltage mode PGA. As used herein, unless otherwise specifically stated, the terms "programmable gain amplifier" and "PGA" cover both current mode TIAs and voltage mode PGAs.

[0036] Note that the LNA 120, mixer 125, and TIA 131 constitute the second gain control region 122 of the receiver 100 (where these components may be collectively referred to as the "LMT" block). Although the embodiments are not limited in this regard, in one particular embodiment, the second gain control region 122 may have a controllable gain ranging from 0 dB to 33 dB (e.g., nominally with a two dB step).

[0037] Still referring to Figure 1 , the output of the TIA 131 is provided to a low-pass filter (LPF) 140 for low-pass filtering. In one embodiment, the LPF 140 may be implemented by a biquadratic filter 142. Although Figure 1 not shown in the figure for ease of illustration, the LPF 140 may include a PGA to control the gain of the biquadratic filter 142. In the illustrated embodiment, the LPF 140 constitutes the third gain control region 144. Although the embodiments are not limited in this regard, in one particular embodiment, the third gain control region 144 may have a controllable gain between -10 dB and 20 dB (e.g., with a two dB step). Note that in Figure 1 the implementation, additional anti-aliasing filtering may be performed by RC components (i.e., resistor R3 and capacitor C3). The filtered IF signal output from the LPF 140 is provided to a digitizer, i.e., an analog-to-digital converter (ADC) 160.

[0038] Note that Figure 1 this discussion of

[0039] Still referring to Figure 1 , the digitized output (ADC_Out) of the ADC 160 is provided to a digital signal processor (DSP) 170. The DSP 170 may analyze the output of the channel filtering to determine the received signal strength indicator (RSSI) information, which (as described herein) may be used in some cases to perform fine-tuning of one or more gain components. The DSP 170 may also digitally process and output the processed data.

[0040] Still referring to Figure 1, the RF signal after attenuation in the attenuator 110 is also provided to a first peak detector 115, which operates as a broadband detector to compare the power of the RF signal output from the attenuator 110 with a first threshold (Pth1). The first peak detector 115 can operate to sense the incoming signal in the RF and provide an estimate of an incoming unwanted blocker that is offset from the desired signal. For example, the offset can be 400 MHz away and the blocker can be 80 MHz wide. Thus, the first peak detector 115 mainly helps to improve out-of-band blocking performance and coexistence. When the RF signal level exceeds this threshold, the peak detector 115 outputs an active detection signal RFPKD to the AGC controller 180 (details of which are described below). Although the embodiments are not limited in this regard, in one particular embodiment, the first threshold Pth1 can be set at -22 dBm (for AGC SENS mode) and -30 dBm (for AGC ACI mode). Of course, in other embodiments, other values are possible.

[0041] As further illustrated, the IF signal output from the TIA 130 is provided to another peak detector 135, which is an IF peak detector in the illustrated embodiment. The peak detector 135 operates as a broadband detector to compare the IF signal power with a second threshold (Pth2). The peak detector 135 operates to estimate an 80 MHz channel (along with the filtering from the TIA 130). In one embodiment, the second threshold Pth2 can be set at -8 dBm (for AGC SENS mode) and -18 dBm (for AGC ACI mode), although of course other values are also possible. The peak detector 135 located at the output of the TIA 130 provides an indication of the headroom limit and can sense saturation conditions (such as LTE signals) for all blockers in ACI, AACI, and OOB blockers. As discussed above, when the IF signal level exceeds this threshold, the peak detector 135 outputs an active detection signal IFPKD to the AGC controller 180.

[0042] In the case of an embodiment without such a properly located IF detector (e.g., instead located at the filter output), since the blocker level may be undetectable (due to lower gain or higher filtering at the LNA input), the combination of the RF and such differently located IF power detectors (e.g., further downstream in the receiver signal processing path) may not be sufficient to decouple the noise-linearity trade-off. For one embodiment, information about the signal level at the TIA output (possibly along with the RSSI-based signal level) may enable different gain backoffs and AGC operations to achieve optimal linearity and headroom performance.

[0043] Figure 1 A digital peak detector 165 coupled to the output of the ADC 160 is also shown. Although shown as a separate component, it should be understood that in some embodiments, the ADC 160 may perform peak detection as part of the digitization, thereby substantially making such peak detection "free" (e.g., when the ADC 160 is implemented as a successive approximation register ADC). This digital peak detector can be used to detect the saturation level because it contains blocker information (since it is located before the channel selection filter in the DSP 170). The digital peak detector 165 operates to compare this digital output with another threshold. In one embodiment, the threshold may be set at -4 dBm (for the AGC SENS mode) and -18 dBm (for the AGC ACI mode), although of course other values are possible. As discussed above, when the digital signal level exceeds this threshold, the peak detector 165 outputs an active detection signal DIGPKD to the AGC controller 180.

[0044] Also, through the above-described example gain controllability for the first, second, and third gain control regions, the overall receiver can have a controllable gain (Gtotal) of a total of 102 dB from -40 dB to 62 dB. More specifically, each of the individual controllable gain control regions can have a maximum gain setting of 9 dB, 33 dB, and 20 dB respectively (corresponding to max(G1, G2, G3)).

[0045] In one embodiment, the AGC controller 180 may be implemented as a dedicated microcontroller or other programmable hardware control circuit, such as programmable logic. In other cases, the AGC controller 180 may be implemented using other hardware circuits, firmware, software, and / or combinations thereof to control the gain settings of various gain components within the receiver 100 based on the detected outputs from one or more of the peak detectors 115, 135, and 165. Additionally, it should be understood that the AGC controller 180 can efficiently perform this gain control within a small time window (e.g., entirely within the preamble portion of the data communication) such that no payload data of the communication is lost.

[0046] As further illustrated, the AGC controller 180 includes a storage device 185, which in an embodiment may be implemented as a non-volatile storage device or other non-transitory storage medium. The non-volatile storage device 185 may store a table containing a plurality of entries, each for storing a set of predetermined gain settings for various gain components of the receiver 100, such that under the control of the gain controller 180, the settings of the selected group can be accessed and used to update the gain settings of the corresponding gain components within the receiver 100. At least two such tables may be provided, one for the AGC SENS mode and one for the AGC ACI mode.

[0047] Note that the predetermined gain settings can be used to populate the table because the characteristics of the receiver known a priori are used to determine these gain settings (e.g., during the design time) as confirmed during laboratory testing of the actual receiver (such as a manufactured integrated circuit). In this way, it is ensured that these predetermined settings, when used by the controller as described herein to perform AGC operations during the preamble portion of a packet communication, enable the receiver to perform the receive operation in a manner that can achieve an optimal trade-off between sensitivity and ACI performance under varying channel conditions.

[0048] Now referring Figure 2 , a flowchart of a method according to an embodiment is shown. More specifically, method 200 is a method for performing automatic gain control as described herein. Thus, method 200 may be performed by an AGC controller (such as Figure 1 the AGC controller 180) to perform AGC during the preamble portion of a packet communication.

[0049] As illustrated, method 200 begins by setting the gain components of the receiver to their maximum gain settings for the AGC SENS mode (block 205). Next, control passes to diamond 210, where it is determined whether a packet is being received within the receiver. If so, then at diamond 215 it is determined whether the RF power level exceeds a given threshold (e.g., based on a signal from an RF power detector). Note that this threshold level may be programmable. If it is determined that the RF power level exceeds the threshold, then control passes to block 220, where the RF gain setting may be updated based on the RF power level. This is the case because with a high incoming power level, either there is a strong blocker or the desired signal is very strong and would benefit from front-end backoff so that the receiver circuitry does not become saturated.

[0050] Depending on the implementation, various gain settings may be updated. Referring back Figure 1, the gain settings of one or more RF front-end gain components (e.g., resistive and capacitive attenuators) can be updated. Specifically, one or more of these components can back off their gain settings to reduce the power level received in the LNA.

[0051] Still referring to Figure 2 , if it is determined that the RF power level does not exceed the threshold, control then passes to diamond 230 to determine whether the IF power level exceeds a given threshold. Referring back Figure 1 , the IF power level is measured via an IF peak detector coupled to the output of an IF gain stage (e.g., a TIA or a PGA). If the power level is exceeded, control passes to block 240.

[0052] At block 240, the receiver transitions to the AGC ACI mode. This transition can be achieved by switching from using the AGC SENS mode table to using the AGC ACI mode table. Still further, the gain settings for the filter gain components can be updated based on the detected IF power level. Depending on the implementation, the filter gain settings can be updated by backing off its gain (either completely or via iterative reduction). For the purposes of method 200, it is assumed that the filter gain settings are completely backed off at block 240. Of course, in other implementations, there may be iterative filter gain setting updates (by smaller gain reductions and continued analysis of the IF power level) to determine whether the power level still exceeds the threshold.

[0053] Still referring to Figure 2 of the implementation, control passes from block 240 to diamond 245 to determine whether the IF power level still exceeds the threshold. In this implementation, this determination thus indicates whether the IF power level still exceeds the threshold when the filter gain settings have been completely backed off. If the IF power level does exceed the threshold, control passes to block 250, where the PGA gain settings can be updated based on the power level. For example, a small iterative gain reduction can be performed. Then, control passes back to diamond 245 to determine whether the IF power level still exceeds the threshold. This loop between diamond 245 and block 250 occurs until the IF power level no longer exceeds the threshold.

[0054] Still referring to Figure 2, at block 260, the RSSI value can be monitored. It should be understood that this RSSI value is a digital representation of the signal strength and can be used to further control the gain components of the receiver. At diamond 270, it is determined whether the RSSI value exceeds a given threshold. If not, further monitoring occurs at block 260. When it is determined that the RSSI value does exceed the threshold, control passes from diamond 270 to block 280. At block 280, one or more gain components can be updated in a predetermined order based on the mode (SENS or ACI) in which the receiver is operating. That is, in the SENS mode, filter gain fallback occurs before LMT and / or attenuator fallback. Conversely, in the ACI mode, LMT and / or attenuator fallback may occur at least partially before filter fallback. With this arrangement, in the absence of blocker information, the AGC controller uses RSSI information for fine gain control to detect the signal level in the channel (as filtered by one or more filters). Although shown at this high level in the Figure 2 embodiment, many variations and alternatives are possible.

[0055] Now referring to Figure 3A , a graphical illustration of a gain queue for the AGC sensitivity mode according to an embodiment is shown. As Figure 3A shown, illustration 310 shows dynamic gain control (on the Y-axis) as compared to the input RF signal level (on the X-axis). In this illustration, the varying gain levels of different gain components are shown.

[0056] Specifically, as shown in the inset, the gain control levels are illustrated for each of the passive network (PN, e.g., resistive attenuator and / or capacitive attenuator (CapATT)), LMT stage (GM), and filter stage. As illustrated in the sensitivity mode, as the incoming signal level increases from a low level to a high level, the filter gain is first backed off. Thereafter, one or more components of the LMT block are backed off. Then the passive network is backed off, and additional LMT block fallback occurs. Finally, when the signal level is relatively high, the capacitive attenuator can be reduced while the filter gain can be increased. Of course, although shown in this specific example in Figure 3A , there can be many variations to the AGC operation.

[0057] It should be understood that in order to affect these dynamic gain control changes, the AGC controller can access the information present in one or more gain tables. There can be at least one gain table for the SENS mode that has multiple entries to store gain settings for corresponding power levels. As an example, each gain component can have multiple gain settings, each associated with a given detected power level (detected by a relevant power detector).

[0058] Now refer to Figure 3B , which shows a graphical illustration of a gain queue for the AGC ACI mode according to an embodiment. Illustration 320 is similar to Figure 3A the arrangement in

[0059] Now refer to Figure 3C and Figure 3D , which shows a graphical illustration of the signal levels of incoming RF signals for varying power at different points in the receiver signal processing path based on gain control according to an embodiment (i.e., Figure 3C the signal levels for the AGC SENS mode in Figure 3D and the signal levels for the AGC ACI mode in

[0060] As illustrated, in graphical illustrations 330 and 340, the linear portions of the curves representing the signal power at the respective receiver signal processing points (as RFIn increases) mean that no gain adjustment is taking place there. Then, when at or near a given threshold (for a given peak detector), the relatively stable signal power means that the gain of a given gain block is reduced as the RFin signal strength increases. It should also be noted that different thresholds can be used in different AGC modes, and it should also be noted that the gain changes are different (e.g., based on table values).

[0061] Thus, the embodiment configures the receiver in an optimal noise profile, i.e., the sensitivity mode (when the IF peak detector threshold is not reached). Conversely, when the IF peak detector threshold is reached, the receiver is configured in an optimal linearity profile, i.e., the ACI mode. This breaks the fundamental trade-off across different conditions (such as for IEEE 802.11a / b / g / n / ax and 20 / 40 / 80 MHz bandwidths) and can provide optimal noise and linearity performance in real time. In other words, the embodiment provides an improvement in sensitivity and blocking performance relative to the two different AGC modes, thereby allowing decoupling of the trade-off across different conditions.

[0062] Now refer to Figure 4 , which shows a block diagram of a typical integrated circuit 400 that includes a controllable AGC circuit for dynamically switching between AGC control modes as described herein. In Figure 4In the illustrated embodiments, the integrated circuit 400 can be, for example, a dual-mode wireless transceiver that can operate according to one or more wireless protocols (e.g., WLAN and Bluetooth, etc.), or other devices that can be used in a variety of use cases. In one or more embodiments, Figure 4 The circuitry of the integrated circuit 400 illustrated in

[0063] The integrated circuit 400 can be included in a range of devices, including a variety of stations, including smartphones, wearable devices, smart home devices, other consumer devices, or industrial, scientific, and medical (ISM) devices, etc.

[0064] In the illustrated embodiments, the integrated circuit 400 includes a memory system 410, which in one embodiment can include volatile storage devices (such as RAM) and non-volatile memory (such as flash memory). As further illustrated, optionally, the integrated circuit 400 can also include a separate flash memory 490 (or other non-volatile memory). The flash memory 490 can be implemented as a non-transitory storage medium that can store instructions and data. Such non-volatile memory can store instructions, including instructions for identifying conditions that can trigger a change in the AGC control mode (as described herein).

[0065] The memory system 410 is coupled to the digital core 420 via a bus 450. The digital core 420 can include one or more cores and / or microcontrollers, which act as the main processing unit of the integrated circuit. In turn, the digital core 420 can be coupled to a clock generator 430, which can provide one or more phase-locked loops or other clock generator circuits to generate various clocks for use by the circuitry of the IC.

[0066] As further illustrated, the IC 400 also includes a power circuit 440, which can include one or more voltage regulators. Depending on the specific implementation, additional circuitry can optionally be present to provide various functionality and interaction with external devices. Such circuitry can include an interface circuit 460, which can provide a LAN or other interface with various off-chip devices, and a security circuit 470, which can perform wireless security techniques.

[0067] In addition, as Figure 4As shown, a transceiver circuit 480 can be provided to enable reception and transmission of wireless signals, for example, according to one or more of local or wide-area wireless communication schemes, such as Zigbee, Bluetooth, IEEE 802.11, IEEE 802.15.4, cellular communication, or the like. As shown, the transceiver circuit 480 includes AGC tables 485 1-n, which can be dynamically selected based on signal detection metrics to provide gain control information for multiple AGC modes, including the AGCSENS and AGCACI modes (as described herein). It should be understood that while shown from this high-level perspective, many variations and alternatives are possible.

[0068] An IC such as described herein can be implemented in a variety of different devices, such as a wireless station, an IoT device, or the like. Now referring to Figure 5 , a high-level diagram of a network according to an embodiment is shown. As Figure 5 shown, the network 500 includes a variety of devices, including wireless stations (including smart devices such as IoT devices), access points, and remote service providers, which can utilize the embodiment to dynamically switch between different AGC control modes based at least in part on signal measurements at multiple points in the receiver signal processing path.

[0069] In Figure 5 an embodiment, there is a wireless network 505, for example, in a building having multiple wireless devices 510 0-n . As shown, the wireless devices 510 are coupled to an access point 530, which in turn communicates with a remote service provider 560 via a wide-area network 550 (e.g., the Internet). It should be understood that while shown in Figure 5 this high-level in an embodiment, many variations and alternatives are possible.

[0070] Although the invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. The appended claims are intended to cover all such modifications and variations as fall within the true spirit and scope of the present invention as presented.

Claims

1. A receiver, comprising: a low noise amplifier (LNA) for receiving and amplifying a radio frequency (RF) signal; a mixer for down-converting the RF signal to an intermediate frequency (IF) signal; a programmable gain amplifier (PGA) coupled to the mixer to amplify the IF signal, the LNA, the mixer, and the PGA having a first controllable gain; a filter coupled to the PGA to filter the amplified IF signal, the filter having a second controllable gain; a digitizer coupled to the filter to digitize the filtered IF signal into a digitized signal; a first power detector coupled to an input of the LNA, the first power detector configured to output a first detection signal in response to the RF signal exceeding a first threshold; a second power detector coupled to the output of the PGA, the second power detector configured to output a second detection signal in response to the IF signal exceeding a second threshold; as well as A controller is provided for transitioning from an automatic gain control (AGC) sensitivity (SENS) mode to an AGC adjacent channel interference (ACI) mode in response to the second detection signal.

2. The receiver of claim 1, wherein: In the AGCACI mode, the controller is to first back off the second controllable gain and thereafter back off the first controllable gain.

3. The receiver of claim 2, further comprising at least one RF gain component coupled to an input of the LNA, the at least one RF gain component having a third controllable gain, wherein: After the backing off of the first controllable gain, the controller is to back off the third controllable gain.

4. The receiver of claim 3, wherein: The controller is then to remove the third controllable gain, and if the signal metric information exceeds a third threshold, the controller is to further adjust the first controllable gain.

5. The receiver of claim 2, wherein: In the AGC SENS mode, the controller is to first back off the second controllable gain and thereafter back off the first controllable gain.

6. The receiver of claim 1, wherein: In response to the first detection signal, the controller is to directly back off the gain of at least one RF gain component.

7. The receiver of claim 6, wherein: In response to the first detection signal, the controller is to directly back off the gain of the at least one RF gain component until the first detection signal indicates that the RF signal is less than the first threshold.

8. The receiver of claim 1, wherein: In the AGC SENS mode, the controller is to optimize the receiver for noise performance; as well as In the AGC ACI mode, the controller is to optimize the receiver for linearity and headroom.

9. The receiver of claim 8, wherein: In the AGC SENS mode, the controller is to cause a maximum RF gain setting for at least the LNA.

10. The receiver of claim 9, wherein: In the AGC SENS mode, the controller is to cause the maximum RF gain setting for at least the LNA unless a blocker signal is detected.

11. The receiver of claim 8, further comprising a plurality of gain tables, wherein: At least one first gain table is associated with the AGC SENS mode, and at least one second gain table is associated with the AGC ACI mode.

12. A method comprising: setting, via a controller of the receiver, a plurality of gain components of the receiver for a maximum gain setting for an automatic gain control (AGC) sensitivity (SENS) mode; receiving, in a controller of the receiver, an indication that a power level of an intermediate frequency (IF) signal measured at an output of an IF amplifier of the receiver exceeds a first threshold, the IF signal being derived from a radio frequency (RF) signal received in the receiver; and Responsive to the indication that the power level of the IF signal exceeds the first threshold, a transition is made from the AGC SENS mode to an AGC adjacent channel interference (ACI) mode.

13. The method of claim 12, further comprising dynamically adjusting gain settings for one or more of the plurality of gain components of the receiver based on a received signal strength indication obtained from a digital processor of the receiver.

14. The method of claim 13, wherein: Dynamically adjusting the gain setting for one or more gain components of the plurality of gain components includes: for the AGC SENS mode, dynamically adjusting the gain settings for the one or more gain components of the plurality of gain components in a first order; and For the AGCACI mode, the gain settings for the one or more gain components of the plurality of gain components are dynamically adjusted in a second order.

15. The method of claim 12, further comprising: In response to the indication that the power level of the IF signal exceeds the first threshold, a gain setting of a filter of the receiver, the filter coupled to an output of the IF amplifier, is adjusted.

16. The method of claim 12, further comprising: receiving, in the controller of the receiver, an indication that a power level of the RF signal exceeds a second threshold; as well as In response to the indication that the power level of the RF signal exceeds the second threshold, a gain setting for at least one RF gain component of the receiver is dynamically adjusted.

17. The method of claim 12, further comprising: In the AGC SENS mode, optimizing the receiver for noise performance; as well as In the AGC ACI mode, the receiver is optimized for linearity.

18. A wireless device comprising: an antenna for transmitting radio frequency (RF) signals and for receiving RF signals; as well as an integrated circuit (IC), the IC coupled to the antenna, the IC comprising: an attenuator controllable to attenuate the received RF signal, the attenuator comprising a first gain control region; a low noise amplifier (LNA), the LNA coupled to the attenuator, the LNA for receiving and amplifying the received RF signal; a mixer for down-converting the received RF signal into an intermediate frequency (IF) signal; an IF amplifier coupled to the mixer to amplify the IF signal, the LNA, the mixer, and the IF amplifier comprising a second gain control region; a filter coupled to the IF amplifier to filter the amplified IF signal, The filter includes a third gain control region; a digitizer coupled to the filter to digitize the filtered IF signal into a digitized signal; a digital signal processor (DSP), the DSP coupled to the digitizer, the DSP configured to process the digitized signal; a first power detector coupled to the output of the attenuator, the first power detector configured to output a first detection signal in response to the received RF signal output from the attenuator exceeding a first threshold; a second power detector coupled to the output of the IF amplifier, the second power detector being configured to output a second detection signal in response to the amplified IF signal exceeding a second threshold; and A controller is provided for transitioning from an automatic gain control (AGC) sensitivity (SENS) mode to an AGC adjacent channel interference (ACI) mode in response to the second detection signal.

19. The wireless device of claim 18, further comprising a storage device to store a plurality of gain tables, wherein At least one first gain table is associated with the AGC SENS mode, and at least one second gain table is associated with the AGC ACI mode.

20. The wireless device of claim 18, wherein: The controller shall: dynamically adjusting the first gain control region, the second gain control region, and the third gain control region in a first order for the AGC SENS mode; as well as The first gain control region, the second gain control region, and the third gain control region are dynamically adjusted in a second order for the AGC ACI mode.

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