Filter Selection Techniques for Isolating a Receiver from a Transmission Signal in a Wireless Communication Device

Abstract

In one implementation, a wireless communication device includes a first transceiver and a band-pass filter (BPF) selection circuit. The first transceiver is configured to generate a transmission signal, and the BPF selection circuit is configured to filter the transmission signal through one of a first BPF having a relatively high-frequency passband or a second BPF having a relatively low-frequency passband. The wireless communication device includes a second transceiver that is configured to receive a received signal filtered by the other of the first BPF or the second BPF. Filtering the transmission signal and the received signal through two different passband filters improves the isolation between the transmitter and the receiver. Another implementation configures the first transceiver to include its own set of first and second BPFs and configures the second transceiver to also include its own first and second BPFs.

Description

Technical Field

[0001] Aspects of the present disclosure generally relate to transceivers, and more particularly to techniques for selecting transmit and receive filters to substantially isolate a receiver from transmit signals in a wireless communication device. Background Art

[0002] A wireless transceiver typically includes a power amplifier (PA) on the transmitter side of the transceiver and a low noise amplifier (LNA) on the receiver side of the transceiver. If the isolation between the transmitter and the receiver is poor, the signal transmitted by the transmitter will leak into the input of the LNA. To prevent the LNA from saturating due to the leaked transmit signal, the gain of the LNA is reduced. However, reducing the gain of the LNA reduces the sensitivity to detect the intended received signal. Therefore, improving the isolation between the transmitter and the receiver is of interest. Summary of the Invention

[0003] The following is a simplified overview of one or more embodiments to provide a basic understanding of such embodiments. This overview is not an extensive overview of all contemplated embodiments, and is neither intended to identify key or critical elements of all embodiments nor to delineate any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description presented later.

[0004] One aspect of the present disclosure relates to an apparatus. The apparatus includes a first wireless transceiver having an output; a second wireless transceiver having an input; a first filter; a second filter; a first antenna; a second antenna; a first set of switching devices; and a second set of switching devices, the first set of switching devices being configured to selectively couple the output of the first wireless transceiver to the first filter or the second filter and selectively couple the input of the second wireless transceiver to the second filter or the first filter, the second set of switching devices being configured to selectively couple the first filter or the second filter to the first antenna and selectively couple the second filter or the first filter to the second antenna.

[0005] Another aspect of the present disclosure relates to a method. The method includes generating a transmit signal, filtering the transmit signal using one of a first filter response or a second filter response, receiving a receive signal, and filtering the receive signal using the other of the first filter response or the second filter response.

[0006] Another aspect of the present disclosure relates to an apparatus. The apparatus includes means for generating a transmit signal, means for filtering the transmit signal using one of a first filter response or a second filter response, means for receiving a receive signal, and means for filtering the receive signal using the other of the first filter response and the second filter response.

[0007] Another aspect of the present disclosure relates to an apparatus. The apparatus includes a first transceiver subsystem. The first transceiver subsystem includes a transmitter front end, a first filter, a second filter, a first antenna, a first set of one or more switching devices configured to selectively couple the transmitter front end to the first filter or the second filter, and a second set of one or more switching devices configured to selectively couple the first filter or the second filter to the first antenna. The apparatus further includes a second transceiver subsystem. The second transceiver subsystem includes a receiver front end, a third filter, a fourth filter, a second antenna, a third set of one or more switching devices configured to selectively couple the receiver front end to the third filter or the fourth filter, and a fourth set of one or more switching devices configured to selectively couple the third filter or the fourth filter to the second antenna.

[0008] Another aspect of the present disclosure relates to a method. The method includes generating a transmission signal, filtering the transmission signal using a selected one of a first filter response or a second filter response, receiving a received signal, and filtering the received signal using a selected one of a third filter response or a fourth filter response.

[0009] Another aspect of the present disclosure relates to an apparatus. The apparatus includes means for generating a transmission signal, means for filtering the transmission signal using a selected one of a first filter response or a second filter response, means for receiving a received signal, and means for filtering the received signal using a selected one of a third filter response or a fourth filter response.

[0010] To achieve the above and related purposes, one or more embodiments include the features fully described hereinafter and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative aspects of one or more embodiments. However, these aspects merely indicate some of the various ways in which the principles of the embodiments may be employed, and the description of the embodiments is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A block diagram of an example wireless communication system in accordance with one aspect of the present disclosure is shown.

[0012] Figure 2 A diagram showing the spectrum and frequency response of an example channel and filters in accordance with another aspect of the present disclosure is shown.

[0013] Figure 3 A block diagram of an example wireless communication device in accordance with another aspect of the present disclosure is shown.

[0014] Figure 4AA block diagram of an example wireless communication device in a first configuration in accordance with another aspect of the present disclosure is shown.

[0015] Figure 4B A block diagram of an example wireless communication device in a second configuration in accordance with another aspect of the present disclosure is shown. Figure 4A is shown.

[0016] Figure 5A A block diagram of an example wireless communication device in a first configuration in accordance with another aspect of the present disclosure is shown.

[0017] Figure 5B A block diagram of an example wireless communication device in a second configuration in accordance with another aspect of the present disclosure is shown. Figure 5A is shown.

[0018] Figure 6 A flowchart of an example method of transmitting and receiving signals in accordance with another aspect of the present disclosure is shown.

[0019] Figure 7 A flowchart of another example method of transmitting and receiving signals in accordance with another aspect of the present disclosure is shown. DETAILED DESCRIPTION

[0020] The following detailed description in conjunction with the accompanying drawings is intended to describe various configurations and is not intended to represent the only configurations in which the concepts described herein can be practiced. The detailed description includes specific details for providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0021] Figure 1 A block diagram of an example wireless communication system 100 in accordance with one aspect of the present disclosure is shown. The wireless communication system 100 includes a customer premises equipment (CPE) 130, which is a wireless communication device configured to wirelessly communicate with different devices according to different protocols, respectively.

[0022] For example, the CPE 130 is configured to wirelessly transmit a wireless local area network (WLAN) signal 120 via an antenna 132 to one or more other wireless communication devices, such as device 110 (e.g., a smart phone, a computer, a laptop, a tablet device, an Internet of Things (IoT) device, etc.). The WLAN signal 120 may conform to any 802.11 protocol, such as 802.11ax specified by the Institute of Electrical and Electronics Engineers (IEEE), which is commonly referred to as WiFi.

[0023] Similarly, CPE 130 is configured to wirelessly transmit a cellular (Wireless Wide Area Network (WWAN)) network signal 140 to one or more other wireless communication devices, such as cellular base station 150, via another antenna 134. The cellular network signal 140 may conform to any cellular protocol, such as the fourth generation (4G) (which is commonly referred to as Long Term Evolution (LTE)) specified by the 3rd Generation Partnership Project (3GPP), or the fifth generation (5G) (which is commonly referred to as New Radio (NR) 5G) specified by 3GPP.

[0024] Typically, as the name implies, CPE 130 is located in a residential or commercial building, and the wireless communication device 110 is located near CPE 130 such that both devices 110 and 130 are able to communicate with each other via the WLAN signal 120. On the other hand, the base station 150 may be located far away from the residential or commercial building where CPE 130 is located such that the base station 150 and CPE 130 are able to communicate with each other via the cellular signal 140.

[0025] In some cases, the base station 150 may send data intended for the wireless communication device 110 to the CPE 130, where the cellular signal 140 is in an unlicensed spectrum. This is commonly referred to as an "offloading" solution because the cellular network offloads the licensed spectrum for data transmission to the wireless communication device 110 and uses the unlicensed spectrum. However, the "offloaded" unlicensed spectrum is consistent with the spectrum used by the CPE 130 to communicate with the wireless communication device 110.

[0026] Figure 2 A diagram showing the spectrum and frequency response of an example channel and filter according to another aspect of the present disclosure is shown. The x-axis or horizontal axis of the diagram represents frequency (f), and the y-axis or vertical axis represents power (e.g., in decibel-milliwatts (dBm)) and filter response (in decibels (dB)). The above-mentioned unlicensed spectrum may have four (4) sub-bands (SBs), such as SB46A, SB46B, SB46C, and SB46D.

[0027] In terms of frequency range, sub-band SB46A (which is commonly referred to as Unlicensed National Information Infrastructure (U-NII)-1) extends from 5150 megahertz (MHz) to 5250 MHz; sub-band SB 46B (which is the lower sub-band of U-NII-2) extends from 5250 MHz to 5350 MHz; sub-band SB 46C (which is the higher sub-band of U-NII-2) extends from 5450 MHz to 5725 MHz; sub-band 46D (which is commonly referred to as U-NII-3) extends from 5725 MHz to 5825 MHz. Sub-band 46A or U-NII-1 has five (5) channels for data transmission, sub-bands 46B and 46C or U-NII-2 have 18 channels for data transmission, and sub-band 46D or U-NII-3 has three (3) channels for data transmission.

[0028] Since the CPE 130 uses unlicensed sub-bands for the reception of cellular signals 140 from the base station 150 and for the transmission of WLAN signals 120 to the wireless communication device 110, the reception of cellular signals 140 by the CPE 130 may be interfered with by the WLAN signals 120 transmitted by the CPE 130. This is further explained herein with reference to several examples.

[0029] Figure 3 A block diagram of an exemplary wireless communication device 300 in accordance with another aspect of the present disclosure is shown. The wireless communication device 300 may be an exemplary implementation of the CPE 130. The wireless communication device 300 includes a WLAN transceiver (Tx / Rx) subsystem 310 and a cellular transceiver subsystem 350.

[0030] More specifically, the WLAN Tx / Rx subsystem 310 includes a WLAN transceiver 320, a WLAN transmitter front end 330, and an antenna 340. The WLAN transceiver 320 is configured to generate radio frequency (RF) signals via one or more channels in a selected one of sub-bands 46A-46D for the transmission of data to, for example, the wireless communication device 110. The WLAN transmitter front end 330 includes a power amplifier (PA) that is configured to amplify the power of the RF signal and provide the amplified RF signal to the antenna 340 for transmission to one or more wireless communication devices, such as device 110. Although not shown, the WLAN Tx / Rx subsystem 310 includes a WLAN receiver (Rx) front end coupled to the WLAN transceiver 320 to receive signals from one or more wireless communication devices, such as device 110.

[0031] Similarly, the cellular Tx / Rx subsystem 350 includes a cellular transceiver 360, a cellular receiver (Rx) front end 370, and an antenna 380. The antenna 380 is configured to receive RF signals via one or more channels in a selected one of subbands 46A - 46D for reception of data from, for example, the base station 150. The WLAN receiver front end 370 includes a low noise amplifier (LNA) configured to perform low noise amplification on the RF signals and provide the amplified RF signals to the cellular transceiver 360 for further processing to obtain data transmitted by the base station 150. Although not shown, the cellular Tx / Rx subsystem 350 includes a cellular transmitter (Tx) front end coupled to the cellular transceiver 360 to transmit signals to the base station 150.

[0032] Since WLAN transmission and cellular reception use the same subbands, there should be significant isolation between antennas 340 and 380 to prevent signals transmitted by the WLAN Tx / Rx subsystem 310 from adversely affecting the reception of signals by the LNA of the cellular receiver front end 370 (e.g., by reducing the sensitivity of the LNA due to lower gain such that the LNA is not saturated by the transmitted signal) or to prevent damage to the LNA itself. As an example, if the output power of the signal transmitted by the WLAN Tx / Rx subsystem 310 is 30 dBm and the maximum tolerable signal level at the LNA input is 15 dBm, the isolation between antenna 340 and antenna 380 should be greater than 15 dB (with zero tolerance), such as 20 dB (with 5 dB tolerance) or 25 dB (with 10 dB tolerance). A higher tolerance ensures less adverse impact on the expected signals received by the cellular receiver front end 370 and a lower risk of LNA damage due to transmitted signals. However, as wireless communication devices are continuously redesigned in smaller form factors, it becomes more difficult to achieve the desired antenna - to - antenna isolation.

[0033] Figure 4A A block diagram of an example wireless communication device 400 in a first configuration is shown according to another aspect of the present disclosure. Similarly, the wireless communication device 400 can be an example implementation of the CPE 130 discussed previously. In summary, the wireless communication device 400 communicates with the base station 150 and the wireless communication device 110 to communicate on respective channels that are significantly separated in frequency, thereby reducing interference of the WLAN transmission signal with the reception of the cellular reception signal.

[0034] For example, the wireless communication device 400 may establish one or more channels for receiving data signals from the base station 150 within a lower sub-band of the unlicensed spectrum (such as sub-bands 46A and / or 46B), and establish one or more channels for transmitting data signals to the wireless communication device 110 within a higher sub-band of the unlicensed spectrum (such as sub-bands 46C and / or 46D). Alternatively, the wireless communication device 400 may establish one or more channels for receiving data signals from the base station 150 within a higher sub-band of the unlicensed spectrum (such as sub-bands 46C and / or 46D), and establish one or more channels for transmitting data signals to the wireless communication device 110 within a lower sub-band of the unlicensed spectrum (such as sub-bands 46A and / or 46B).

[0035] In conjunction with channel allocation, the wireless communication device 400 includes a high-frequency band-pass filter (H-BPF) and a low-frequency BPF (L-BPF). As Figure 2 shown, the H-BPF may be configured to have a filter response with a passband (e.g., 3 dB passband) that is substantially consistent with the combined frequency range of sub-bands 46C and 46D (e.g., from 5450 MHz to 5825 MHz). The L-BPF may be configured to have a filter response with a passband (e.g., 3 dB passband) that is substantially consistent with the combined frequency range of sub-bands 46A and 46B (e.g., from 5150 MHz to 5350 MHz). Additionally, the filter responses of the H-BPF and L-BPF should provide minimum signal suppression at other passbands, such as -50 dB suppression. Each of the H-BPF and L-BPF described herein may be configured as a bulk acoustic wave filter (BAW), a surface acoustic wave filter (SAW), an LC filter, a ceramic filter, a passive on glass (POG) filter.

[0036] As an example, if the wireless communication device 400 has established one or more channels for transmitting WLAN signals within sub-bands 46A and / or 46B and one or more channels for receiving cellular signals within sub-bands 46C and / or 46D, then the wireless communication device 400 uses the L-BPF to filter the WLAN transmission signals and uses the H-BPF to filter the received cellular signals. Similarly, if the wireless communication device 400 has established one or more channels for transmitting WLAN signals within sub-bands 46C and / or 46D and one or more channels for receiving cellular signals within sub-bands 46A and / or 46B, then the wireless communication device 400 uses the H-BPF to filter the WLAN transmission signals and uses the L-BPF to filter the received cellular signals. Channel selection in combination with filter selection improves the isolation between the transmission signal and the LNA input to reduce interference and potential damage.

[0037] More specifically, the wireless communication device 400 includes a WLAN transceiver (Tx / Rx) subsystem 405 and a cellular transceiver (Tx / Rx) subsystem 425. The WLAN Tx / Rx subsystem 405 includes a WLAN transceiver 410, a WLAN transmitter front-end 415, and an antenna 420. Although not shown, the WLAN Tx / Rx subsystem 405 may also include a WLAN receiver front-end coupled to the WLAN transceiver 410. The cellular Tx / Rx subsystem 425 includes an antenna 440, a cellular receiver front-end 435, and a cellular transceiver 430. Although not shown, the cellular Tx / Rx subsystem 425 may also include a cellular transmitter front-end coupled to the cellular transceiver 430.

[0038] The wireless communication device 400 also includes a band-pass filter (BPF) selection circuit 450, which includes a first set of switching devices 455 (e.g., configured as a double-pole double-throw (DPDT) switch), a high-frequency BPF (H-BPF) 460, a low-frequency BPF (L-BPF) 465, and a second set of switching devices 470 (e.g., also configured as a DPDT switch).

[0039] The DPDT switch 455 includes a first pole P1 coupled to the output of the WLAN transceiver 410 and a second pole P2 coupled to the input of the cellular receiver front-end 435 (e.g., LNA). The DPDT switch 455 also includes a first set of throws T 11 and T 12 associated with the first pole P1 and coupled to the H-BPF 460 and the L-BPF 465, respectively. In addition, the DPDT switch 455 also includes a second set of throws T 21 and T 22 associated with the second pole P2 and coupled to the L-BPF 465 and the H-BPF 460, respectively.

[0040] The DPDT switch 470 includes a first pole P1 coupled to the input of the WLAN transmitter front-end 415 and a second pole P2 coupled to the antenna 440. The DPDT switch 470 also includes a first set of throws T 11 and T 12 associated with the first pole P1 and coupled to the H-BPF 460 and the L-BPF 465, respectively. In addition, the DPDT switch 470 also includes a second set of throws T 21 and T 22 associated with the second pole P2 and coupled to the L-BPF 465 and the H-BPF 460, respectively. The WLAN Tx front-end includes an output coupled to the antenna 420.

[0041] As discussed, the H-BPF 460 can have a filter frequency response whose passband substantially coincides with the combined frequency range of sub-bands 46C and 46D, and has a specified minimum rejection in the frequency ranges of sub-bands 46A and 46B, as previously referenced Figure 2 As discussed. Similarly, the L-BPF 465 can have a filter frequency response whose passband substantially coincides with the combined frequency range of sub-bands 46A and 46B, and has a specified minimum rejection in the frequency ranges of sub-bands 46C and 46D, as previously referenced Figure 2 As discussed.

[0042] The wireless communication device 400 includes a controller 480 for channel selection and control of the BPF selection circuit 450. The controller 480 is shown coupled to the cellular transceiver 430 to communicate with the base station 150 to select one or more channels in which to receive cellular signals. Although not shown, the controller 480 can be coupled to the WLAN transceiver 410 to communicate with the wireless communication device 110 to select one or more channels in which to transmit WLAN signals. There can be many different ways to select these channels, but the controller selects the one or more cellular channels to be in one of sub-bands 46A / 46B or sub-bands 46C / 46D, and selects the one or more WLAN channels to be in the other of sub-bands 46A / 46B or sub-bands 465C / 46C.

[0043] For example, if the controller 480 selects one or more channels for transmitting WLAN signals within sub-bands 46C and / or 46D, and selects one or more channels for receiving cellular signals within sub-bands 46A and / or 465B, then the controller 480 sends control signals (CS) to the DPDT switches 455 and 470 to couple the first pole P1 to the throw T in both DPDT switches 11 and couple the second pole P2 to the throw T in both DPDT switches 21 . In this first configuration, the WLAN transceiver 410, H-BPF 460, WLAN Tx front-end 415, and antenna 420 are coupled in series; and the antenna 440, L-BPF 465, cellular Rx front-end (LNA) 435, and cellular transceiver 430 are coupled in series. Thus, the wireless communication device 400 filters the WLAN transmission signals using the H-BPF 460 and filters the received cellular signals using the L-BPF 465. As discussed, filtering the transmission signals using the filter response of the H-BPF 460 and filtering the received signals using the filter response of the L-BPF 465 results in sufficient rejection of the transmission signals at the input of the cellular receiver front-end (LNA) 435, thereby significantly reducing interference and potential damage to the LNA.

[0044] Figure 4B FIG. shows a block diagram of an example wireless communication device 400 in a second configuration according to another aspect of the present disclosure. In the second configuration, the controller 480 selects one or more channels for transmitting WLAN signals within subbands 46A and / or 46B, and selects one or more channels for receiving cellular signals within subbands 46C and / or 465C. Accordingly, the controller 480 sends control signals (CS) to the DPDT switches 455 and 470 to couple the first pole P1 to the throw T in both DPDT switches 12 and couple the second pole P2 to the throw T in both DPDT switches 22 . In the second configuration, the WLAN transceiver 410, L-BPF 465, WLAN Tx front end 415, and antenna 420 are coupled in series; and the antenna 440, H-BPF 460, cellular Rx front end (LNA) 435, and cellular transceiver 430 are coupled in series. Accordingly, the wireless communication device 400 filters the WLAN transmission signals using the L-BPF 465, and filters the received cellular signals using the H-BPF 460. As discussed, filtering the transmission signals using the filter response of the L-BPF 465 and filtering the received signals using the filter response of the H-BPF 460 results in sufficient suppression of the transmission signals at the input of the cellular receiver front end (LNA) 435, thereby significantly reducing interference and potential damage to the LNA.

[0045] Figure 5A FIG. shows a block diagram of an example wireless communication device 500 in a first configuration according to another aspect of the present disclosure. The wireless communication device 500 may be an example implementation of the previously discussed CPE 130. The wireless communication device 500 is a variant of the wireless communication device 400, with the main difference being that the WLAN Tx / Rx subsystem has its own set of H-BPFs and L-BPFs, and the cellular Tx / Rx system has its own set of H-BPRs and L-BPRs.

[0046] More specifically, the wireless communication device 500 includes a WLAN transceiver (Tx / Rx) subsystem 505 and a cellular transceiver (Tx + Rx) subsystem 550. The WLAN Tx / Rx subsystem 505 includes a WLAN transceiver 510, a WLAN transmitter front-end 515, a band-pass filter (BPF) selection circuit 520, and an antenna 545. Although not shown, the WLAN Tx / Rx subsystem 505 may also include a WLAN receiver front-end coupled to the WLAN transceiver 510. The BPF selection circuit 520 includes a first set of one or more switching devices 525 (e.g., configured as single-pole double-throw (SPDT) switches), a high-frequency BPF (H-BPF) 530, a low-frequency BPF (L-BPF) 535, and a second set of one or more switching devices 540 (e.g., also configured as SPDT switches).

[0047] The WLAN transceiver 510 is configured to generate a WLAN transmission signal. The WLAN transmitter front-end 515 includes a power amplifier (PA) configured to amplify the WLAN transmission signal. The SPDT switch 525 includes a pole P coupled to the output of the WLAN front-end 515, a first throw T1 coupled to the H-BPF 530, and a second throw T2 coupled to the L-BPF 535. The SPDT switch 540 includes a first throw T1 coupled to the H-BPF 530, a second throw T2 coupled to the L-BPF, and a pole P coupled to the antenna 545. In a first configuration, the BPF selection circuit 520 has a pole P coupled to the first throw T1 of both the SPDT switches 525 and 540. Accordingly, the WLAN transceiver 510, the WLAN transmitter front-end 515, the H-BPF 530, and the antenna 545 are coupled in series.

[0048] The cellular Tx / Rx subsystem 550 includes a cellular transceiver 555, a cellular receiver front-end 585, a band-pass filter (BPF) selection circuit 560, and an antenna 590. Although not shown, the cellular Tx / Rx subsystem 550 may also include a cellular transmitter front-end coupled to the cellular transceiver 555. The BPF selection circuit 560 includes a first set of one or more switching devices 565 (e.g., configured as single-pole double-throw (SPDT) switches), a high-frequency BPF (H-BPF) 570, a low-frequency BPF (L-BPF) 575, and a second set of one or more switching devices 580 (e.g., also configured as SPDT switches).

[0049] The antenna 590 is configured to wirelessly receive a cellular reception signal. The SPDT switch 580 includes a pole P coupled to the antenna 590, a first throw T1 coupled to the H-BPF 570, and a second throw T2 coupled to the L-BPF 575. The SPDT switch 565 includes a first throw T1 coupled to the H-BPF 570, a second throw T2 coupled to the L-BPF 575, and a pole P coupled to the input of the cellular Rx front end (LNA) 585. The cellular Rx front end 585 is configured to perform low-noise amplification on the filtered cellular reception signal. The cellular transceiver 555 is configured to process the amplified and filtered cellular reception signal to recover data from the signal. In the first configuration, the BPF selection circuit 560 has a pole P coupled to the second throw T2 of both the SPDT switches 580 and 565. Thus, the antenna 590, the L-BPF 575, the cellular Rx front end 585, and the cellular transceiver 555 are coupled in series.

[0050] As discussed, each of the H-BPFs 530 and 570 can have a filter frequency response whose passband substantially coincides with the combined frequency range of subbands 46C and 46D and has a specified minimum rejection in the frequency ranges of subbands 46A and 46B, as previously referenced Figure 2 As discussed. Similarly, each of the L-BPFs 535 and 575 can have a filter frequency response whose passband substantially coincides with the combined frequency range of subbands 46A and 46B and has a specified minimum rejection in the frequency ranges of subbands 46C and 46D, as previously referenced Figure 2 As discussed.

[0051] The wireless communication device 500 includes a controller 595 for channel selection and control of the BPF selection circuits 520 and 560. The controller 595 is shown coupled to the cellular transceiver 555 to communicate with the base station 150 to select one or more channels in which to receive cellular signals. Although not shown, the controller 595 can be coupled to the WLAN transceiver 510 to communicate with the wireless communication device 110 to select one or more channels in which to transmit WLAN signals. There can be many different ways to select these channels, but the controller 595 selects the one or more cellular channels to be in one of subbands 46A / 46B or subbands 46C / 46C, and selects the one or more WLAN channels to be in the other of subbands 46A / 46B or subbands 465C / 46C.

[0052] In a first configuration, the controller 595 selects one or more channels for transmitting the WLAN signal within sub-bands 46C and / or 46D, and selects one or more channels for receiving the cellular signal within sub-bands 46A and / or 46B. Accordingly, the controller 595 sends control signals (CS) to the SPDT switches 525 and 540 to couple pole P to the first throw T1 of the two SPDT switches. The controller 595 also sends control signals (CS) to the SPDT switches 565 and 580 to couple pole P to the second throw T2 of the two SPDT switches.

[0053] Accordingly, in this first configuration, the WLAN transceiver 510, the WLAN Tx front-end 515, the H-BPF 530, and the antenna 545 are coupled in series; and the antenna 590, the L-BPF 575, the cellular Rx front-end (LNA) 585, and the cellular transceiver 555 are coupled in series. Accordingly, the wireless communication device 500 filters the WLAN transmission signal using the H-BPF 530 and filters the received cellular signal using the L-BPF 575. As discussed, filtering the transmission signal using the filter response of the H-BPF 530 and filtering the received signal using the filter response of the L-BPF 575 results in sufficient suppression of the transmission signal at the input of the cellular receiver front-end (LNA) 585, thereby significantly reducing interference and potential damage to the LNA.

[0054] Figure 5B A block diagram of an example wireless communication device 500 in a second configuration is shown in accordance with another aspect of the present disclosure. In the second configuration, the controller 595 selects one or more channels for transmitting the WLAN signal within sub-bands 46A and / or 46B, and selects one or more channels for receiving the cellular signal within sub-bands 46C and / or 46D. Accordingly, the controller 595 sends control signals (CS) to the SPDT 525 and 540 to couple pole P to the second throw T2 of the two SPDTs. The controller 595 also sends control signals (CS) to the SPDT 565 and 580 to couple pole P to the first throw T1 of the two SPDTs.

[0055] Accordingly, in the second configuration, the WLAN transceiver 510, the WLAN Tx front-end 515, the L-BPF 553, and the antenna 545 are coupled in series; the antenna 590, the H-BPF 570, the cellular receiver front-end (LNA) 585, and the cellular transceiver 555 are coupled in series. Accordingly, the wireless communication device 500 filters the WLAN transmission signal using the L-BPF 534 and filters the received cellular signal using the H-BPF 570. As discussed, filtering the transmission signal using the filter response of the L-BPF 535 and filtering the received signal using the filter response of the H-BPF 570 result in sufficient suppression of the transmission signal at the input of the cellular receiver front-end (LNA) 585, thereby significantly reducing interference and potential damage to the LNA.

[0056] Figure 6 A flowchart of an example method 600 for transmitting and receiving signals in accordance with another aspect of the present disclosure is shown. Method 600 includes generating a transmission signal (block 610). Examples of components for generating the transmission signal include the WLAN transceiver 410 discussed previously.

[0057] Method 600 further includes filtering the transmission signal with one of a first filter response or a second filter response (block 620). Examples of components for filtering the transmission signal with one of a first filter response or a second filter response include Figure 4A the first configuration shown or Figure 4B the BPF selection circuit 450 of the second configuration shown, as previously described.

[0058] Method 600 further includes receiving a received signal (block 630). Examples of components for receiving the received signal include the antenna 440 discussed previously.

[0059] In addition, method 600 includes filtering the received signal with the other of a first filter response or a second filter response (block 640). Examples of components for filtering the received signal with the other of a first filter response or a second filter response include Figure 4B the second configuration shown or Figure 4A the BPF selection circuit 450 of the first configuration shown, as previously described.

[0060] Figure 7 A flowchart of an example method 700 for transmitting and receiving signals in accordance with another aspect of the present disclosure is shown. Method 700 includes generating a transmission signal (block 710). Examples of components for generating the transmission signal include the WLAN transceiver 510 or the WLAN transmitter front-end 515 discussed previously.

[0061] Method 700 also includes filtering the transmitted signal with a selected one of the first filter response or the second filter response (block 720). Examples of components for filtering the transmitted signal with a selected one of the first filter response or the second filter response include Figure 5A the first configuration shown or Figure 5B the BPF selection circuit 520 of the second configuration shown, as described above.

[0062] Method 700 also includes receiving a received signal (block 730). Examples of components for receiving the received signal include the antenna 590 discussed previously.

[0063] In addition, method 700 includes filtering the received signal with a selected one of the third filter response or the fourth filter response (block 740). Examples of components for filtering the received signal with a selected one of the third filter response or the fourth filter response include Figure 5A the first configuration shown or Figure 5B the BPF selection circuit 560 of the second configuration shown, as described above.

[0064] Although in the examples provided herein, the BPF selection circuit has been described with respect to substantially isolating the input of a cellular (WWAN) transceiver (LNA) from the transmitted signal of a WLAN transceiver, it should be understood that the BPF selection circuit can also be used to substantially isolate the input of a WLAN transceiver (LNA) from the transmitted signal of a cellular or WWAN transceiver; or for other applications where signal isolation is required between a transmitter and a receiver.

[0065] The previous description of the present disclosure has been provided to enable a person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device, comprising: A first transceiver, including an output; A second transceiver, including an input; A first filter; A second filter; A first antenna; A second antenna; A first set of switching devices, configured to: Selectively couple the output of the first transceiver to the first filter or the second filter; And Selectively couple the input of the second transceiver to the second filter or the first filter; And A second set of switching devices, configured to: Selectively couple the first filter or the second filter to the first antenna; Selectively couple the second filter or the first filter to the second antenna, and A transmitter front-end coupled between the second set of switching devices and the first antenna and a receiver front-end coupled between the first set of switching devices and the second transceiver.

2. The device according to claim 1, wherein the first filter includes a first band-pass filter (BPF) and the second filter includes a second band-pass filter (BPF), wherein the passband of the first BPF is different from the passband of the second BPF.

3. The device according to claim 2, wherein the passband of the first BPF extends from 5150 megahertz (MHz) to 5350 MHz, and the passband of the second BPF extends from 5450 MHz to 5825 MHz.

4. The device according to claim 2, wherein the first BPF is configured to provide a first minimum signal suppression at the passband of the second BPF, and the second BPF is configured to provide a second minimum signal suppression at the passband of the first BPF.

5. The device according to claim 4, wherein the first minimum signal suppression or the second minimum signal suppression includes -50 decibels (dB).

6. The device according to claim 1, wherein the first filter or the second filter includes any one of the following: a bulk acoustic wave filter (BAW), a surface acoustic wave filter (SAW), an LC filter, a ceramic filter, or a passive on glass (POG) filter.

7. The device according to claim 1, wherein the first set of switching devices includes a double-pole double-throw (DPDT) switch, the DPDT switch including a first pole coupled to the output of the first transceiver, a second pole coupled to the input of the second transceiver, a first throw associated with the first pole respectively coupled to the first filter and the second filter, and a third pole and a fourth pole associated with the second pole respectively coupled to the second filter and the first filter.

8. The apparatus according to claim 1, wherein the second set of switching devices includes a double-pole double-throw (DPDT) switch, the DPDT switch including a first pole coupled to the first antenna, a second pole coupled to the second antenna, a first throw and a second throw associated with the first pole and respectively coupled to the first filter and the second filter, and a third pole and a fourth pole associated with the second pole and respectively coupled to the second filter and the first filter.

9. The apparatus according to claim 1, wherein the first transceiver is configured to generate a wireless local area network (WLAN) signal, and wherein the second transceiver is configured to receive a cellular network signal.

10. The apparatus according to claim 1, wherein the transmitter front end includes a power amplifier.

11. The apparatus according to claim 1, wherein the receiver front end includes a low noise amplifier (LNA).

12. The apparatus according to claim 1, further comprising a controller configured to control the first set of switching devices and the second set of switching devices, wherein the controller is configured to control the first set of switching devices and the second set of switching devices such that the first transceiver, the first filter, and the first antenna are coupled in series, and the second transceiver, the second filter, and the second antenna are coupled in series.

13. The apparatus according to claim 1, further comprising a controller configured to control the first set of switching devices and the second set of switching devices, wherein the controller is configured to control the first set of switching devices and the second set of switching devices such that the first transceiver, the second filter, and the first antenna are coupled in series, and the second transceiver, the first filter, and the second antenna are coupled in series.

14. The apparatus according to claim 1, wherein the first transceiver is configured to transmit a first signal within a frequency range, wherein the second transceiver is configured to receive a second signal within the frequency range, wherein the first filter has a first passband within the frequency range, wherein the second filter has a second passband within the frequency range, and the first passband does not overlap with the second passband.

15. A method for operating an apparatus according to any one of claims 1-14, comprising: generating a transmission signal; filtering the transmission signal using one of a first filter response or a second filter response; receiving a received signal; and filtering the received signal using the other of the first filter response or the second filter response.

16. The method according to claim 15, further comprising low noise amplifying the filtered received signal; and power amplifying the filtered transmission signal.

17. An apparatus for wireless communication, comprising: a WLAN transceiver including transmission circuitry coupled to a first antenna along a transmission path, the transmission circuitry being configured to transmit a signal via the first antenna within a frequency range; A WWAN transceiver, comprising a receiving circuit system coupled to a second antenna along a receiving path, the receiving circuit system being configured to receive a signal via the second antenna within the frequency range; A first filter having a passband within a first portion of the frequency range; A second filter having a passband within a second portion of the frequency range different from the first portion, A first set of switching devices configured to: Selectively couple the output of the WLAN transceiver to the first filter or the second filter; And Selectively couple the input of the WWAN transceiver to the second filter or the first filter; A second set of switching devices configured to: Selectively couple the first filter or the second filter to the first antenna; And Selectively couple the second filter or the first filter to the second antenna; And A transmitter front-end coupled between the second set of switching devices and the first antenna and a receiver front-end coupled between the first set of switching devices and the WWAN transceiver.

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