Wireless device using a shared gain stage for simultaneous reception of multiple protocols

A wireless device that can process signals according to multiple wireless protocols simultaneously and without signal loss. The wireless device may comprise an antenna and first and second wireless protocol circuitry. The first wireless protocol circuitry comprises a shared gain element that amplifies signals that are processed by each of the first and second wireless protocol circuitry. Since the third signals are amplified by the shared gain element prior to being split out to the respective protocol circuitry, the first and second portions of the amplified third signals do not have significant signal loss relative to the third signals provided by the antenna. Thus the wireless device can receive and process wireless signals according to both the first and second protocols simultaneously without any significant signal losses due to splitting of the receive signal.

BACKGROUND OF THE INVENTION

1. Field of the Disclosure

The present invention relates generally to wireless communication, and more particularly to reception of wireless signals of different wireless protocols using a shared gain stage to reduce signal loss.

2. Description of the Related Art

Wireless communication is being used for a plethora of applications, such as in laptops, cell phones, and other wireless communication devices (“wireless devices”). In fact, wireless communication is becoming so widely used, it is common for wireless devices to be able to communicate using a plurality of different wireless communication protocols. Accordingly, it is common for a wireless device to have different circuit portions that implement different wireless protocols.

When a wireless device receives a wireless signal on its antenna, the signal is converted to baseband and then provided (split) to the different circuit portions that implement the different wireless protocols. In one prior art implementation, a splitter is placed before the signal is provided to the different circuit portions. Thus only half of the original signal energy is provided to each of the different circuit portions. As a result, each of the split signals suffers a 3 dB loss in sensitivity. In another prior art implementation, the device uses a switch to switch the signal to the different circuit portions. However, only one circuit portion may be used at a time, and the device is not able to simultaneously receive multiple signals of different wireless protocols. Therefore, improvements in wireless devices are desired.

SUMMARY OF THE INVENTION

Embodiments of the invention relate to a wireless device that can process signals according to multiple wireless protocols simultaneously and without signal loss. The wireless device may comprise an antenna for receiving wireless signals, first wireless protocol circuitry, and second wireless protocol circuitry. The first wireless protocol circuitry is coupled to the antenna and configured to receive first signals from the antenna and process the first signals according to the first wireless protocol. The second wireless protocol circuitry is coupled to the antenna and configured to receive second signals from the antenna and process the second signals according to the second wireless protocol. The first wireless protocol circuitry may comprise at least one shared gain element, i.e., a gain element that amplifies signals that are processed by each of the first and second wireless protocol circuitry. In other words, the at least one shared gain element may be utilized for amplifying signals for both the first wireless protocol circuitry and the second wireless protocol circuitry.

When the wireless device is receiving third signals having components according to both the first and second wireless protocols, the first wireless protocol circuitry receives the third signals from the antenna, and the shared gain element amplifies the third signals to produce amplified third signals. At least a first portion of the amplified third signals is processed by the first wireless protocol circuitry, and at least a second portion of the amplified third signals is provided from the first wireless protocol circuitry to the second wireless protocol circuitry for processing. Thus when both the first and second wireless protocol circuitry is operating, the third signals are provided first to the first wireless protocol circuitry, where the third signals are amplified and then split out for processing to the respective first and second wireless protocol circuitry.

Since the third signals are amplified by the shared gain element prior to being split out to the respective protocol circuitry, the first and second portions of the amplified third signals do not have significant signal loss relative to the third signals provided by the antenna. Thus the wireless device can receive and process wireless signals according to both the first and second protocols simultaneously without any significant signal losses due to splitting of the receive signal.

In one embodiment, the first wireless protocol circuitry is configured to dynamically adjust a gain of the shared gain element to provide signals of appropriate signal strength to the first wireless protocol circuitry and the second wireless protocol circuitry. For example, the second wireless protocol circuitry may be configured to provide to the first wireless protocol circuitry information regarding signal strength of signals received by the second wireless protocol circuitry from the first wireless protocol circuitry. The first wireless protocol circuitry may dynamically adjust the gain of the shared gain element based at least in part on this signal strength information.

In addition, the second wireless protocol circuitry may be configured to indicate to the first wireless protocol circuitry when the second wireless protocol circuitry is actively receiving a packet. The first wireless protocol circuitry may be configured to not adjust the gain of the shared gain element while the second wireless protocol circuitry is actively receiving a packet.

One embodiment of the invention relates to a chip for use in a wireless device that implements a first wireless protocol. The chip is intended to operate in a wireless device that implements the first wireless protocol as well as a second wireless protocol. The chip may comprise first wireless protocol circuitry configured to process received first signals according to the first wireless protocol and a gain element coupled to the first wireless protocol circuitry. The chip is configured to receive second signals having components according to both the first wireless protocol and the second wireless protocol. The gain element on the chip is configured to amplify the second signals to produce amplified second signals, wherein a first portion of the amplified second signals is processed by the first wireless protocol circuitry, and a second portion of the amplified second signals is provided external to the chip for processing.

Another embodiment relates to a chip for use in a wireless device that implements a second wireless protocol, wherein the chip is intended to operate in a wireless device that implements a first wireless protocol and the second wireless protocol. The chip may comprise a first input that receives first signals that only have components according to the second wireless protocol. The chip may also comprise a second input configured to receive amplified second signals having components according to both the first and second wireless protocols. The chip may further comprise second wireless protocol circuitry coupled to the first input and the second input. The second wireless protocol circuitry may be configured to process the first signals and the amplified second signals according to the second wireless protocol. The chip may further comprise a switch coupled between the first input, the second input and the second wireless protocol circuitry for selectively providing either the first signals or the amplified second signals to the second wireless protocol circuitry.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIGS. 1A and 1Billustrate an exemplary wireless device100, according to one embodiment. As shown inFIG. 1A, the wireless device100may be a portable computer or other mobile computing device. Alternatively, as shown inFIG. 1B, the wireless device100may be a cell phone or smart phone or other similar mobile device (which may also be classified as a mobile computing device). However, it should be noted that other wireless devices are envisioned, such as personal digital assistants, multimedia players (portable or stationary), routers, and/or other mobile devices/computing systems which are operable to use wireless communication.

The wireless device100may be configured to perform wireless communication using a first wireless protocol and/or a second wireless protocol. For example, the wireless device100may be configured to perform wireless communication using only the first wireless protocol, using only the second wireless protocol, or simultaneously using both the first and second wireless protocol. The first and second wireless protocols may be any of various types of protocols. In some embodiments, the first wireless protocol may be a WLAN protocol. Additionally, the second wireless protocol may be a short range wireless communication protocol, such as Bluetooth. As used herein, a short range wireless protocol may refer to wireless protocols which support distances of up to 1 meter to 10 meters, or in higher powered devices, 100 meters.

FIG.2—Exemplary Block Diagram of the Wireless Device

As shown inFIG. 2, the wireless device100may include device circuitry120(for performing various functions of the wireless device), first wireless protocol circuitry130, and second wireless protocol circuitry140. Each of the first wireless protocol circuitry130and the second wireless protocol circuitry140may be implemented in any of various ways, such as analog logic, digital logic, a processor and memory (such as a CPU, DSP, microcontroller, etc.), an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), or any combination of the above.

The first wireless protocol circuitry130may be comprised on a first chip, and the second wireless protocol circuitry140may be comprised on a second chip. As used herein, the term “chip” has the full extent of its ordinary meaning, and includes an electronic device, e.g., a semiconductor device, that may be implemented in any of the ways described above for the first wireless protocol circuitry130and the second wireless protocol circuitry140.

In one exemplary embodiment, the first wireless protocol circuitry130may be WLAN circuitry130and the second wireless protocol circuitry140may be Bluetooth circuitry140. The WLAN circuitry130and the Bluetooth140circuitry may be co-located, e.g., may be located in the same wireless device100. The device100may include logic for providing a received signal to each of the first wireless protocol circuitry130and the second wireless protocol circuitry140without any loss in sensitivity.

In one embodiment, the wireless device100may include a shared gain element that is used by both the first wireless protocol circuitry130and the second wireless protocol circuitry140. The shared gain element may be comprised in the first wireless protocol circuitry130in one embodiment. The term “shared gain element” refers to a gain element (such as an amplifier, gain stage, etc.) that amplifies signals such that portions of the amplified signals are provided to each of the first and second wireless protocol circuitry130and140(or141,FIGS. 4 and 5), respectively.

Additionally, the wireless device100may include one or more wireless or wired ports for communicating over a network. The wireless device100(e.g., the device circuitry120) may further include one or more memory mediums and processors for implementing various functionality. The wireless device100may operate as described herein.

FIG.3—Exemplary System Diagram of the Wireless Device

FIG. 3is an exemplary system diagram of the wireless device100. As shown, the wireless device100may comprise the first wireless protocol circuitry130(e.g., WLAN) and the second wireless protocol circuitry140(e.g., Bluetooth). As discussed below, the first wireless protocol circuitry130may be considered as comprising a shared gain element (LNA)242, or alternatively the first wireless protocol circuitry130may be considered as being coupled to the shared gain element (LNA)242.

As shown, the device100may comprise an antenna201for receiving signals. The received signal from the antenna201is provided to a diplexer202. The diplexer202may provide one output to a cellular coexistence filter204, and may provide a second output to the single pole double throw (SP2T) switch208. The output of the cellular coexistence filter204is provided to a single pole triple throw (SP3T) switch206. The SP3T switch206has a first connection211to the Bluetooth block140, and has second and third connections212and213to the WLAN block130.

When only the Bluetooth block140is operating, i.e., when only Bluetooth signals are being received or transmitted, the antenna201is in communication with the Bluetooth block140through the SP3T switch206and through the connection211. Thus, when only the Bluetooth block140is operating, the antenna201communicates with the Bluetooth block140in a bidirectional fashion through the connection211. A received Bluetooth signal on the antenna201is provided through SP3T switch206over connection211to SP2T switch280in the Bluetooth block140.

When only the WLAN block130is operating, i.e., when only wireless LAN signals are being received or transmitted, the antenna201is in communication with the WLAN block130through the SP3T switch206and the connections212and213, as well as through the SP2T switch208and connections215and216. The connection212is used for WLAN signals received by the antenna201destined for the WLAN block130, and the connection213is used for WLAN signals generated by the WLAN block130and destined for the antenna201. The connections215and216are used for processing 5 GHz WLAN signals such as those described by IEEE 802.11a (in contrast to the 2.4 GHz WLAN signals through connections212and213). The WLAN (in this implementation at least, but not necessarily for all possible implementations) may operate at either 2 or 5 GHz, and in one embodiment not in both frequencies at the same time. The diplexer202efficiently splits the high and low frequencies, and thus receiving of shared signals (shared Rx) may occur when the WLAN is operating at 2 GHz. The 5 GHz path is only shown for completeness.

Note that references to “only Bluetooth signals being received” refers to signals being received that comprise Bluetooth signals intended for the wireless device100, but not WLAN signals intended for the wireless device100. It is noted that there may be various other signals present in the signal from other sources, such as other Bluetooth signals or other WLAN signals that are not intended for the wireless device100. Similarly, references to “only WLAN signals being received” refers to signals being received that comprise WLAN signals intended for the wireless device100, but not Bluetooth signals intended for the wireless device100. It is noted that there may be various other signals present in the signal from other sources, such as other Bluetooth signals or other WLAN signals that are not intended for the wireless device100.

When both the WLAN block130and the Bluetooth block140are operating, i.e., when both WLAN signals and Bluetooth signals are being received simultaneously, then in one embodiment signals received from the antenna201are provided to the WLAN block130via connection212. The signals may be provided through optional external low noise amplifier (xLNA)220to the WLAN block130. The signals received from connection212and optional xLNA220may be provided through the low noise amplifier (LNA)242in the WLAN block130. The WLAN block130may perform various WLAN processing on the received signals.

The WLAN block130may in turn provide the received signal from LNA242to splitter243. The splitter243may operate to split the signal energy, with a first portion of the signal energy being provided to the remainder of the WLAN block130, and a second portion of the signal energy being provided to the output driver244. The second portion of the signal energy is provided by the output driver244to the Bluetooth block140. The splitter243may or may not be equal, e.g., it may provide more energy to one path and less to the other path if desired. In one embodiment, the WLAN block130dynamically controls the operation of the splitter243, including the amount of signal energy provided to each of the WLAN block130and the Bluetooth block140.

Note that the signal is provided from the WLAN block130to the Bluetooth block140after being amplified by one or more LNAs220and242. In one embodiment, the signal is amplified by 20 dB prior to being split by splitter243and provided to the Bluetooth block140through driver244. Thus, after being amplified by 20 dB, a 3 dB loss due to the splitting of the signal does not impact the signal to noise ratio (SNR) of the signal. Thus the output of LNA242may be split by the splitter243into two paths, with each path having half of the original signal energy, with one half going to the WLAN receiver, and the other half going to driver244and then off the WLAN chip140to the Bluetooth section130.

In one embodiment, the WLAN block130and Bluetooth block140are comprised on separate chips, and the output driver244on the WLAN block130is intended to provide sufficient gain for the signal to be transferred off-chip and across a printed circuit board (PCB) to the chip comprising the Bluetooth block140.

As shown, the Bluetooth block140comprises a LNA288, preferably a variable gain amplifier, that receives the signal from the driver244on the WLAN block130. The LNA288amplifies the received signal to an appropriate size, which is then provided to the remainder of the Bluetooth block140for processing. For example, as shown, the output of the LNA288may be provide to a single pole double throw (SP2T) switch286, where the signal is “switched in” to the Bluetooth logic for processing.

Thus, when both the WLAN block130and the Bluetooth block140are operating, instead of first splitting the received signal and providing these split portions to the WLAN block130and the Bluetooth block140, the signal is not split, but rather is provided to only the WLAN block130. The WLAN block130can amplify the signal through LNA242(and/or driver244) and provide portions of the amplified signal to the Bluetooth block140and the remainder of the WLAN block130. The Bluetooth block140can then operate on the signal received from the WLAN block130. Since the received signal is first amplified on the WLAN block130before being “split out”, the signal does not experience any losses.

In contrast, prior art systems would typically comprise a splitter in place of the SP3T switch206, wherein the splitter split the receive signal and provided portions to the WLAN block130and the Bluetooth block140. Thus in these prior art systems, even when the device was only receiving Bluetooth or only receiving WLAN, the signal would still be split, with half the signal energy being provided to the Bluetooth block140and half the signal energy being provided to the WLAN block130. This results in a 3 dB loss in signal energy, i.e., degrades the sensitivity of each block by 3 dB. Embodiments of the invention described herein operate to allow reception of both Bluetooth and WLAN signals without requiring a loss in signal energy.

FIGS.4and5—Alternate Embodiments with Legacy Bluetooth Sections

FIGS. 4 and 5illustrate alternate embodiments of the device (referred to as100A and100B, respectively) where an existing or legacy Bluetooth chip is included in the system that does not have an input LNA288for receiving a signal from WLAN section130. In other words, inFIG. 3the Bluetooth block140is designed to receive an output signal from the WLAN block130and includes low noise amplifier288and switch286. In the embodiments ofFIGS. 4 and 5, a legacy Bluetooth chip141is used which does not have LNA288and switch286. The embodiment ofFIG. 3may have a lower cost, smaller area, and lower insertion loss than the embodiments ofFIGS. 4 and 5, but utilizes a specially designed Bluetooth block140.

In the embodiment ofFIG. 4(device (100A), the output from driver244is provided over connection402to connection211, and is thereby coupled to the I/O port of the Bluetooth block141. In this embodiment, it is important that line402between the driver244and the SP3T206match properly when the Bluetooth block141is transmitting. As shown, when Bluetooth block141is transmitting, the transmitted signal is provided through SP2T switch280and over connection211to the SP3T switch206. However, as shown, this output Bluetooth signal provided over connection211may also be coupled onto connection402. It is noted that driver404is powered down in this mode, with its output (and the input seen by the BT transmitter) tied to ground. Thus when Bluetooth block141is transmitting the driver244may be shorted to ground, and further device100A may comprise LC phase shifting circuitry (not shown) coupled to trace402to prevent the signal output on connection211from being transmitted onto trace402. The LC phase shifting circuitry may be designed based on the length of the trace402to provide appropriate signal matching.

FIG. 5illustrates an alternative embodiment toFIG. 4(device100B). The embodiment ofFIG. 5is slightly more complex than the embodiment ofFIG. 4, but does not have the signal matching issues that may occur on trace402ofFIG. 4. In the embodiment ofFIG. 5, the SP3T switch206in the embodiments ofFIGS. 3 and 4is essentially replaced with three SP2T switches506,508and510, as shown. More specifically, the cellular coexistence filter204is coupled to a first port of SP2T switch506. The SP2T switch506in turn has a second port that connects over line511to a port of SP2T switch508. Output of output driver244on the WLAN block130is coupled over line402to another port on SP2T switch508. A third port of SP2T switch508connects to Bluetooth block141, e.g., to the SP2T switch280in Bluetooth block141. A third port of SP2T switch506connects to a first port of SP2T switch510. The second and third ports of SP2T switch510connect to LNA220and xPA (Power Amplifier)221as shown.

As shown inFIGS. 6 and 7, the Bluetooth block140may provide various feedback to the WLAN block130to control operation of the WLAN block130. More specifically, the Bluetooth block140may provide feedback to the WLAN block130to enable the blocks130and140to effectively share the LNA242.

In one embodiment, the LNA242is a variable gain LNA as shown, and the WLAN block130may operate to adjust the gain of the LNA242as desired. Optional xLNA220may also have variable gain, or in another embodiment may be able to be turned off for very large signals. When an input signal is very large, the WLAN chip130may choose to turn off the xLNA220and/or set the SP3T206to move away from WLAN Rx mode, to get extra attenuation. These changes are preferably prevented when signal bt_rx_frame is asserted, as discussed below.

As indicated above, the splitter243for providing the first signal to the WLAN block130and the second signal to the Bluetooth block140may not provide signals of equal strength. In one embodiment, for example, the Bluetooth block140may receive a higher powered signal than the signal provided to the WLAN block130. Alternatively, the signal for the WLAN block130may be higher powered. In some embodiments, the proportion of the power of the signals may be adjusted, e.g., based on indications from the WLAN block130and/or the Bluetooth block140. The adjustment may be dynamically performed by the WLAN block130.

It may be desirable to prevent the WLAN block130from adjusting the gain of the LNA242while the Bluetooth block140is receiving a packet, as this may cause the packet to have errors in reception. In other words, if the Bluetooth block140is in the process of receiving a frame, and during this time the WLAN block130adjusts the gain of the LNA242, this will most likely “kill” the Bluetooth packet, i.e., the packet (frame) will not be received properly and an error will be generated.

Thus, as shown inFIG. 6, when the Bluetooth block140(e.g., Bluetooth receiver) determines in602that it is receiving a packet, the Bluetooth block140may in604provide a (digital) signal referred to as bt_rx_frame (shown inFIGS. 3-5) to the WLAN block130(e.g., WLAN receiver). The bt_rx_frame signal thus informs the WLAN block130when the Bluetooth block140is receiving a packet or frame. When the WLAN block130is operating and both the Bluetooth block140and WLAN block130are searching for a frame, the WLAN block130can set the gain of the LNA242as desired. Once the Bluetooth block140determines that it is actively receiving a frame, e.g., by detecting proper receipt of an access code, the Bluetooth block140asserts the bt_rx_frame signal. When the WLAN block130receives the asserted bt_rx_frame signal, at606the WLAN block130refrains from changing the gain of the LNA242. It is noted that the WLAN block130may change other gain settings during the time the bt_rx_frame signal is asserted, but it will not change the gain of the LNA242or the settings of xLNA220or SP3T206. When the Bluetooth block140finishes receiving its frame in608, the Bluetooth block141deasserts the bt_rx_frame signal at610, and the WLAN block130is now able to change the gain of the LNA242.

For some legacy Bluetooth devices, bt_rx_frame may not be available. In other words, legacy Bluetooth devices may not have the capability to generate bt_rx_frame. In this case, the device100A or100B may use another signal that is present, such as a signal from a standard “3-wire” BT/WLAN coexistence interface. In one such example, a signal called BT_Active may be used. This signal is present whenever the Bluetooth device141is actively transmitting or attempting to receive a frame. In one embodiment, the WLAN block130could use BT_active rather than bt_rx_frame. This is sub-optimal, since the WLAN Block130will see the BT_active signal asserted when the Bluetooth block141is just scanning for frames, but it should still provide a benefit. There is little or no harm from the fact that the BT_Active signal is asserted during Bluetooth transmit frames, since the WLAN receiver130will typically not be enabled during Bluetooth transmission (TX). If Bluetooth Transmit is ever enabled while WLAN Receive (Rx) is enabled, the shared Rx system and driver244will be disabled.

FIG. 8illustrates an alternate embodiment of a portion of the circuit (including LNA242and driver244) shown in the WLAN block130ofFIGS. 3-5. As described above inFIGS. 3-5, the LNA242is coupled to splitter243and then to driver244. In one implementation, the WLAN block130includes a peak detector802and comparator804that are also coupled to the output of the LNA242. The peak detector802is coupled to the output of the LNA242. The output of the peak detector802is provided to a comparator804. The comparator804provides its output to the WLAN block130. The peak detector802and comparator804are configured such that if the comparator804triggers, the LNA242is deemed to be in saturation. If this happens while bt_rx_frame is asserted, the WLAN AGC will be free to disregard bt_rx_frame until it deasserts and re-asserts in the future, and in the meantime it may change the LNA gains as it likes. Hence, if a very large signal arrives while a small Bluetooth signal is present, and the very large signal puts the LNA into saturation, the Bluetooth signal will likely not be received anyway, so the WLAN block130should be allowed to adjust its gain in case the new, large signal is a WLAN signal.

When the WLAN block130adjusts the gain of the LNA242(and other gain elements), it may size the gain so that the signal has sufficient signal to noise ratio, while also leaving enough headroom for blocking signals (blockers). The term “blockers” refers to other signals that may exist on the medium in nearby frequencies, which the WLAN receiver130and BT receiver140/141would like to tolerate. Thus the WLAN block130may typically adjust the gain to be the minimum gain necessary to receive a signal. However, consider a situation where the Bluetooth block140is receiving weak signals, and the WLAN block130is receiving stronger signals. Without any modification, the WLAN block130may configure a gain setting that provides enough SNR for the WLAN signals, but inadequate SNR for the Bluetooth signals.

FIG. 7illustrates an embodiment of a method wherein the Bluetooth block140/141provides feedback regarding signal to noise ratio of received signals. In one embodiment, at702software executing on the Bluetooth block140/141periodically accumulates the RSSIs from its communication partners. For example, if the Bluetooth block140is primarily communicating with a headset, the Bluetooth block140/141gathers information on the average received signal strength indicators (RSSI's) for this headset. At704the Bluetooth block140/141provides this information to the WLAN block130, e.g., the average value of the RSSIs. At706the WLAN block130receives and examines this information and may compare it to the average RSSI that it is receiving from the access point (AP) that it is primarily communicating with. If the WLAN block130determines at708that its RSSIs are in general higher than the RSSIs experienced by the Bluetooth block140/141, the WLAN block130at710may decide to increase the gain of the LNA424(and/or change the proportion of the splitter) to provide increased signal strength for the Bluetooth block140.

For example, the WLAN block130may write a value to the WLAN automatic gain control (AGC) block to increase the typical LNA gain setting used to a higher value, thus providing increased signal strength to the Bluetooth block140. The AGC block determines how to allocate the desired gain among the multiple variable gain blocks, so this input from software allows it to modify how much of the variable gain to allocate to the LNA. For example, if a setting of 10 is requested from software, the AGC may set up to 10 dB more of gain in the LNA than it typically might, and would set a correspondingly lower amount of gain in the rest of the receive chain to compensate. This method may operate at a slow adaptation rate, e.g., not on a per frame basis.

To summarize the above discussion ofFIGS. 6 and 7, in some embodiments the Bluetooth (BT) block140/141does not directly control the shared LNA242on the WLAN block130, or the optional xLNA220or SP3T206. The WLAN block130will generally operate the LNA242in a way that it deems appropriate, adapting to changing conditions in the 2.4 GHz band through signal detection at the ADC, and with a peak detector at the LNA output. The BT block140/141will react to the WLAN changes in gain by changing the gain of its own receive chain.

One exception is when the BT block140/141detects reception of a frame, usually through a valid access code correlation. In this case the BT block140/141informs the WLAN block130with a signal called bt_rx_frame that it is actively receiving a frame. During reception of the frame (e.g., while the bt_rx_frame signal is asserted), the WLAN block130is requested to not change the LNA or splitter gain (or any off-chip gain components like an xLNA), and instead may change other gain blocks after the LNA as it sees fit. This will keep the signal stable for the BT receiver while the frame is being received. Once the BT block140/141is done receiving a frame, it will de-assert bt_rx_frame.

In another method, the BT software periodically sends the WLAN software information about the received signal strength (RSSI) of its main communication partner, such as a BT headset it is sending audio to and from. Software executing on the WLAN block130will then compare the BT RSSI to the RSSI of its main communication partner, such as the access point that it is communicating with, to determine which is larger and by how much. The software may then write a register in the AGC that will cause the AGC to change how it partitions the gain between the LNA and the rest of the receive path. For example, if the BT RSSI is lower than the WLAN RSSI, more gain than usual might be requested from the LNA if a WLAN signal were to arrive before bt_rx_frame is asserted. This might harm the ability of WLAN to tolerate much larger blockers, but it would help the BT block140/141be able to receive its signal if it arrives after the WLAN block130has already locked the LNA gain for its own signal. The blocker performance would be decreased, but if these blockers are not detected as being present by the WLAN software, then there is no downside to making this change. Thus this method helps the WLAN block130adjust the LNA gain during normal operation.

As discussed above, if the bt_rx_frame signal cannot be created by the BT block140/141, then other signals from a standard BT/WLAN coexistence interface may be used by the WLAN side to infer bt_rx_frame.