RADIO FREQUENCY MODULE WITH REDUCED INTERMODULATION DISTORTION

A radio frequency module includes a filter having a first portion with a passband corresponding to a first receive frequency band and a second portion with a passband corresponding to at least a portion of a first transmit aggressor frequency band. A signal path is configured to couple between an antenna and the filter. The filter includes an antenna-side port coupled to the signal path. The module further includes a receive amplifier coupled to the first portion of the filter and a tunable termination impedance coupled to the second portion of the filter.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

BACKGROUND

Field

Embodiments of the invention relate to radio frequency (RF) modules and/or wireless communication devices.

Description of the Related Technology

Aspects of this disclosure relate to cellular communication systems, and in particular, to systems for high power uplink transmission for frequency division duplex (FDD) communication systems. The Specific Absorption Rate (SAR) is a measure of the energy absorbed per unit mass by a human body when exposed to a RF electromagnetic field. It can be defined as the power absorbed per mass of tissue in watts per kilogram (W/kg). Cellular user equipment (UE) must measure below Specific Absorption Rate (SAR) regulatory limits, and therefore transmit below a maximum average power in the uplink (UL) between the UE and a base station. For instance, FDD systems which transmit and receive continuously, transmit with a maximum average power below a threshold such that the total radiated power (TRP) complies with relevant SAR limits.

Established cellular communication networks are typically limited in coverage extent by two factors: capacity and the need to provide a target level of data rate and service to a large number of people in a dense area, and/or coverage range which is typically limited by UL power from battery powered mobile handsets or wearable devices.

The capacity issue can be addressed in certain environments via the establishment of smaller cells and densification of the network. Coexistence interference issues can become more prevalent in such radio environments, and thus higher uplink power may not necessarily be favored depending on how the uplink power is scheduled to overcome coexistence challenges.

The UL-limited coverage issue largely the result of an asymmetry in the power between the transmitter from base station and mobile handset. Downlink (DL) power from the base station is typically in the range of 40 W from high performance antennas and typically less than ¼ W from the mobile device. The receivers for both the base station and mobile handset are much closer to one another, both close to the theoretical physical noise limits.

Operation at the cell edge (e.g., when the user is substantially equally distant from multiple base stations) requires the highest power levels and typically reduces the modulation allocation and backs off the order of modulation to narrower bandwidths and simple Quadrature Phase-Shift Keying (QPSK) in order to preserve the signal-to-noise ratio of the UL modulation, LTE being made up of individual resource blocks (RBs). The DL can operate without changes in allocation as the transmission of the entire channel and multiple channels for the DL is typically operated at maximum power from the base station. The UL must work hard and make these trade-offs to preserve UL SNR and maintain the link back to the eNodeB (LTE) or gNodeB (NR).

Additionally, because cellphones are presently used approximately 75% of the time indoors where building penetration (especially at higher frequencies) becomes a significant challenge, cellphones may be effectively operating at the cell edge (e.g., where the link SNR degrades to a point where the link and service is at risk of being dropped, similar to the risks associated at the cell edge).

The call drop statistics and buffering indicated during low data rate periods are perhaps one of the most critical user experience statistics driving customer churn and dissatisfaction and drive much of the consumer perception of the carrier services. In continuous transmission of Frequency-Division Duplex (FDD), UL power is limited by regulatory safety limits of average power-termed Specific Absorbed Radiation (SAR) as indicators of safe amounts of electromagnetic energy absorbed in human tissue. It is not possible to increase the maximum FDD UL power because of this limit, and the Total Radiated Power (TRP) is made as high as possible to meet carrier requirements, while still meeting the regulatory maximum average power based on SAR.

Aspects of this disclosure relate to systems and methods which can provide improved UL power transmission for FDD communication without exceeding the SAR regulatory limit.

SUMMARY

In some aspects, the techniques described herein relate to a radio frequency module including: a filter having a first portion with a passband corresponding to a first receive frequency band and a second portion with a passband corresponding to at least a portion of a first transmit aggressor frequency band; a signal path configured to couple between an antenna and the filter, the filter including an antenna-side port coupled to the signal path; a receive amplifier coupled to the first portion of the filter; and a tunable termination impedance coupled to the second portion of the filter.

In some aspects, the techniques described herein relate to a radio frequency module further including a first switch configured to couple the first portion of the filter to the receive amplifier and the second portion of the filter to the tunable termination impedance.

In some aspects, the techniques described herein relate to a radio frequency module wherein the second portion of the filter includes a dual surface acoustic wave (dual-SAW) mode low power filter.

In some aspects, the techniques described herein relate to a radio frequency module wherein the radio frequency module is a receive-only diversity receive (DRx) module.

In some aspects, the techniques described herein relate to a radio frequency module further including a transmit amplifier configured to amplify a transmit signal, the filter having a third portion coupled to the transmit amplifier and having a passband corresponding to a transmit signal frequency band.

In some aspects, the techniques described herein relate to a radio frequency module further including a second switch configured to couple an output of the transmit amplifier to the third portion of the filter and to couple the second portion of the filter to the tunable termination impedance.

In some aspects, the techniques described herein relate to a radio frequency module wherein the filter includes a third portion with a passband corresponding to a second receive frequency band.

In some aspects, the techniques described herein relate to a radio frequency module wherein the first receive frequency band is a downlink band of 3GPP LTE B1 and the second receive frequency band is a downlink band of 3GPP LTE B3.

In some aspects, the techniques described herein relate to a wireless device including: a radio frequency front end module including a filter having a first portion with a passband corresponding to a first receive frequency band and a second portion with a passband corresponding to at least a portion of a first transmit aggressor frequency band, a signal path configured to couple between an antenna and the filter, the filter including an antenna-side port coupled to the signal path, a receive amplifier coupled to the first portion of the filter, and a tunable termination impedance coupled to the second portion of the filter; a transceiver coupled to the radio frequency front end module; and an antenna coupled to the radio frequency front end module.

In some aspects, the techniques described herein relate to a wireless device further including a first switch configured to couple the first portion of the filter to the receive amplifier and the second portion of the filter to the tunable termination impedance.

In some aspects, the techniques described herein relate to a wireless device wherein the second portion of the filter includes a dual surface acoustic wave (dual-SAW) mode low power filter.

In some aspects, the techniques described herein relate to a wireless device wherein the radio frequency front end module is a receive-only diversity receive (DRx) module.

In some aspects, the techniques described herein relate to a wireless device further including a transmit amplifier configured to amplify a transmit signal, the filter having a third portion coupled to the transmit amplifier and having a passband corresponding to a transmit signal frequency band.

In some aspects, the techniques described herein relate to a wireless device further including a second switch configured to couple an output of the transmit amplifier to the third portion of the filter and to couple the second portion of the filter to the tunable termination impedance.

In some aspects, the techniques described herein relate to a wireless device wherein the filter includes a third portion with a passband corresponding to a second receive frequency band.

In some aspects, the techniques described herein relate to a wireless device wherein the first receive frequency band is a downlink band of 3GPP LTE B1 and the second receive frequency band is a downlink band of 3GPP LTE B3.

In some aspects, the techniques described herein relate to a radio frequency front end system including: a filter having a first portion with a passband corresponding to a first receive frequency band and a second portion with a passband corresponding to at least a portion of a first transmit aggressor frequency band; a signal path configured to couple between an antenna and the filter, the filter including an antenna-side port coupled to the signal path; a receive amplifier coupled to the first portion of the filter; and a tunable termination impedance coupled to the second portion of the filter.

In some aspects, the techniques described herein relate to a radio frequency front end system further including a first switch configured to couple the first portion of the filter to the receive amplifier and the second portion of the filter to the tunable termination impedance.

In some aspects, the techniques described herein relate to a radio frequency front end system wherein the second portion of the filter includes a dual surface acoustic wave (dual-SAW) mode low power filter.

In some aspects, the techniques described herein relate to a radio frequency front end system wherein the radio frequency front end system is a receive-only diversity receive (DRx) module.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG.1is a schematic diagram of one example of a communication network20. The communication network20includes a macro cell base station1, a mobile device2, a small cell base station3, and a stationary wireless device4.

The illustrated communication network20ofFIG.1supports communications using a variety of technologies, including, for example, 4G LTE, 5G NR, and wireless local area network (WLAN), such as Wi-Fi. In the communication network20, dual connectivity can be implemented with concurrent 4G LTE and 5G NR communication with the mobile device2. Although various examples of supported communication technologies are shown, the communication network20can be adapted to support a wide variety of communication technologies.

Various communication links of the communication network20have been depicted inFIG.1. The communication links can be duplexed in a wide variety of ways, including, for example, using frequency-division duplexing (FDD) and/or time-division duplexing (TDD). FDD is a type of radio frequency communications that uses different frequencies for transmitting and receiving signals. FDD can provide a number of advantages, such as high data rates and low latency. In contrast, TDD is a type of radio frequency communications that uses about the same frequency for transmitting and receiving signals, and in which transmit and receive communications are switched in time. TDD can provide a number of advantages, such as efficient use of spectrum and variable allocation of throughput between transmit and receive directions.

As shown inFIG.1, the mobile device2communicates with the macro cell base station1over a communication link that uses a combination of 4G LTE and 5G NR technologies. The mobile device2also communications with the small cell base station3. In the illustrated example, the mobile device2and small cell base station3communicate over a communication link that uses 5G NR, 4G LTE, and Wi-Fi technologies. In certain implementations, enhanced license assisted access (eLAA) is used to aggregate one or more licensed frequency carriers (for instance, licensed 4G LTE and/or 5G NR frequencies), with one or more unlicensed carriers (for instance, unlicensed Wi-Fi frequencies).

In certain implementations, the mobile device2communicates with the macro cell base station2and the small cell base station3using 5G NR technology over one or more frequency bands that are less than 7.5 Gigahertz (GHz) and/or over one or more frequency bands that are greater than 7.5 GHz. For example, wireless communications can utilize Frequency Range1(FR1), Frequency Range2(FR2), or a combination thereof. In one embodiment, the mobile device2supports a HPUE power class specification.

The illustrated small cell base station3also communicates with a stationary wireless device4. The small cell base station3can be used, for example, to provide broadband service using 5G NR technology. In certain implementations, the small cell base station3communicates with the stationary wireless device4over one or more millimeter wave frequency bands in the frequency range of 30 GHz to 300 GHz and/or upper centimeter wave frequency bands in the frequency range of 24 GHz to 30 GHz.

In certain implementations, the small cell base station3communicates with the stationary wireless device4using beamforming. For example, beamforming can be used to focus signal strength to overcome path losses, such as high loss associated with communicating over millimeter wave frequencies.

The communication network20ofFIG.1includes the macro cell base station1and the small cell base station3. In certain implementations, the small cell base station3can operate with relatively lower power, shorter range, and/or with fewer concurrent users relative to the macro cell base station1. The small cell base station3can also be referred to as a femtocell, a picocell, or a microcell.

Although the communication network20is illustrated as including two base stations, the communication network20can be implemented to include more or fewer base stations and/or base stations of other types. As shown inFIG.1, base stations can communicate with one another using wireless communications to provide a wireless backhaul. Additionally or alternatively, base stations can communicate with one another using wired and/or optical links.

The communication network20ofFIG.1is illustrated as including one mobile device and one stationary wireless device. The mobile device2and the stationary wireless device4illustrate two examples of user devices or user equipment (UE). Although the communication network20is illustrated as including two user devices, the communication network20can be used to communicate with more or fewer user devices and/or user devices of other types. For example, user devices can include mobile phones, tablets, laptops, Internet of Things (IoT) devices, wearable electronics, and/or a wide variety of other communications devices.

User devices of the communication network20can share available network resources (for instance, available frequency spectrum) in a wide variety of ways.

In one example, frequency division multiple access (FDMA) is used to divide a frequency band into multiple frequency carriers. Additionally, one or more carriers are allocated to a particular user. Examples of FDMA include, but are not limited to, single carrier FDMA (SC-FDMA) and orthogonal FDMA (OFDMA). OFDMA is a multicarrier technology that subdivides the available bandwidth into multiple mutually orthogonal narrowband subcarriers, which can be separately assigned to different users.

Other examples of shared access include, but are not limited to, time division multiple access (TDMA) in which a user is allocated particular time slots for using a frequency resource, code division multiple access (CDMA) in which a frequency resource is shared amongst different users by assigning each user device a unique code, space-divisional multiple access (SDMA) in which beamforming is used to provide shared access by spatial division, and non-orthogonal multiple access (NOMA) in which the power domain is used for multiple access. For example, NOMA can be used to serve multiple user devices at the same frequency, time, and/or code, but with different power levels.

Enhanced mobile broadband (eMBB) refers to technology for growing system capacity of LTE networks. For example, eMBB can refer to communications with a peak data rate of at least 10 Gbps and a minimum of 100 Mbps for each user device. Ultra-reliable low latency communications (uRLLC) refers to technology for communication with very low latency, for instance, less than 2 milliseconds. uRLLC can be used for mission-critical communications such as for autonomous driving and/or remote surgery applications. Massive machine-type communications (mMTC) refers to low cost and low data rate communications associated with wireless connections to everyday objects, such as those associated with IoT applications.

The communication network20ofFIG.1can be used to support a wide variety of advanced communication features, including, but not limited to eMBB, uRLLC, and/or mMTC.

A peak data rate of a communication link (for instance, between a base station and a user device) depends on a variety of factors. For example, peak data rate can be affected by channel bandwidth, modulation order, a number of component carriers, and/or a number of antennas used for communications.

For instance, in certain implementations, a data rate of a communication link can be about equal to M*B*log2(1+S/N), where M is the number of communication channels, B is the channel bandwidth, and S/N is the signal-to-noise ratio (SNR).

Accordingly, data rate of a communication link can be increased by increasing the number of communication channels (for instance, transmitting and receiving using multiple antennas), using wider bandwidth (for instance, by aggregating carriers), and/or improving SNR (for instance, by increasing transmit power and/or improving receiver sensitivity).

5G NR communication systems can employ a wide variety of techniques for enhancing data rate and/or communication performance.

FIG.2is a schematic diagram of one example of a communication link using carrier aggregation. Carrier aggregation can be used to widen bandwidth of the communication link by supporting communications over multiple frequency carriers, thereby increasing user data rates and enhancing network capacity by utilizing fragmented spectrum allocations. Carrier aggregation can present technical challenges for measuring power of individual carriers. Radio frequency systems disclosed herein can measure power associated with one or more transmit paths in carrier aggregation applications. Embodiments disclosed herein can be implemented in carrier aggregation applications.

In the illustrated example, the communication link is provided between a base station21and a mobile device22. As shown inFIG.2, the communications link includes a downlink channel used for RF communications from the base station21to the mobile device22, and an uplink channel used for RF communications from the mobile device22to the base station21.

AlthoughFIG.2illustrates carrier aggregation in the context of FDD communications, carrier aggregation can also be used for TDD communications.

In certain implementations, a communication link can provide asymmetrical data rates for a downlink channel and an uplink channel. For example, a communication link can be used to support a relatively high downlink data rate to enable high speed streaming of multimedia content to a mobile device, while providing a relatively slower data rate for uploading data from the mobile device to the cloud.

In the illustrated example, the base station21and the mobile device22communicate via carrier aggregation, which can be used to selectively increase bandwidth of the communication link. Carrier aggregation includes contiguous aggregation, in which contiguous carriers within the same operating frequency band are aggregated. Carrier aggregation can also be non-contiguous, and can include carriers separated in frequency within a common band or in different bands.

In the example shown inFIG.2, the uplink channel includes three aggregated component carriers fUL1, fUL2, and fUL3. Additionally, the downlink channel includes five aggregated component carriers fDL1, fDL2, fDL3, fDL4, and fDL5. Although one example of component carrier aggregation is shown, more or fewer carriers can be aggregated for uplink and/or downlink. Moreover, a number of aggregated carriers can be varied over time to achieve desired uplink and downlink data rates.

For example, a number of aggregated carriers for uplink and/or downlink communications with respect to a particular mobile device can change over time. For example, the number of aggregated carriers can change as the device moves through the communication network and/or as network usage changes over time.

FIG.3Ais a schematic diagram of one example of a downlink channel using multi-input and multi-output (MIMO) communications.FIG.3Bis schematic diagram of one example of an uplink channel using MIMO communications.

MIMO communications use multiple antennas for simultaneously communicating multiple data streams over common frequency spectrum. In certain implementations, the data streams operate with different reference signals to enhance data reception at the receiver. MIMO communications benefit from higher SNR, improved coding, and/or reduced signal interference due to spatial multiplexing differences of the radio environment.

MIMO order refers to a number of separate data streams sent or received. For instance, MIMO order for downlink communications can be described by a number of transmit antennas of a base station and a number of receive antennas for UE, such as a mobile device. For example, two-by-two (2×2) DL MIMO refers to MIMO downlink communications using two base station antennas and two UE antennas. Additionally, four-by-four (4×4) DL MIMO refers to MIMO downlink communications using four base station antennas and four UE antennas.

In the example shown inFIG.3A, downlink MIMO communications are provided by transmitting using M antennas43a,43b,43c, . . .43mof the base station41and receiving using N antennas44a,44b,44c, . . .44nof the mobile device42. Accordingly,FIG.3Aillustrates an example of m×n DL MIMO.

Likewise, MIMO order for uplink communications can be described by a number of transmit antennas of UE, such as a mobile device, and a number of receive antennas of a base station. For example, 2×2 UL MIMO refers to MIMO uplink communications using two UE antennas and two base station antennas. Additionally, 4×4 UL MIMO refers to MIMO uplink communications using four UE antennas and four base station antennas.

In the example shown inFIG.3B, uplink MIMO communications are provided by transmitting using N antennas44a,44b,44c, . . .44nof the mobile device42and receiving using M antennas43a,43b,43c, . . .43mof the base station41. Accordingly,FIG.3Billustrates an example of n×m UL MIMO.

By increasing the level or order of MIMO, bandwidth of an uplink channel and/or a downlink channel can be increased.

MIMO communications are applicable to communication links of a variety of types, such as FDD communication links and TDD communication links.

FIG.3Cis schematic diagram of another example of an uplink channel using MIMO communications. In the example shown inFIG.3C, uplink MIMO communications are provided by transmitting using N antennas44a,44b,44c, . . .44nof the mobile device42. Additionally, a first portion of the uplink transmissions are received using M antennas43a1,43b1,43c1, . . .43m1of a first base station41a, while a second portion of the uplink transmissions are received using M antennas43a2,43b2,43c2, . . .43m2of a second base station41b. Additionally, the first base station41aand the second base station41bcommunication with one another over wired, optical, and/or wireless links.

The MIMO scenario ofFIG.3Cillustrates an example in which multiple base stations cooperate to facilitate MIMO communications.

FIG.4is a schematic diagram of a radio frequency module. The radio frequency module comprises a power amplifier61, a switch62, a duplexer63, an antenna switch module64, a coupler66and an antenna tuner69(which can also be referred to as a multiplexer or antenna plexer). The coupler66is implemented between the duplexer63and the antenna switch module64. Alternatively or additionally, the coupler66can be implemented between the antenna switch module64and the antenna tuner69or between the antenna tuner69and an antenna. Where the coupler66placed post the duplexer63, somewhere between the duplexer63and the antenna, there can be a high and phase dependent reflection of an out-of-band back injected blocker. For example, a second transmit signal Tx2from another transmit channel on the radio frequency module can be back-injected at the antenna tuner69or at the antenna switch module64, reflect off of the duplexer63, and result in reverse intermodulation (RIMD), which is out of band (OOB) relative to one or more receive paths.

Certain embodiments described hersein reduce reflection of the back-injected out-of-band Tx2. For example, embodiments herein include a termination of the back-injected second Tx2and the relative phase of that complex impedance can be critical to the overall resulting intermodulation (RIMD).

FIG.5is a schematic diagram of an example of a radio frequency module60according to certain embodiments. In the illustrated example, the radio frequency module60comprises a power amplifier61, a post power amplifier (post-PA) switch62(e.g., a band switch), a filter63, an antenna switch module64, a low noise amplifier65, a directional coupler66and a tunable termination impedance67.

The radio frequency module60comprises a transmit Tx path and a receive Rx path. The receive Rx path is configured for passage of a Rx signal in multiple frequency bands. The filter63can include a pair of frequency division duplexers including a first duplexer for B1having passbands spanning B1Tx and BlRx, respectively, and a second duplexer having passbands spanning B3Tx and B3Rx, respectively. As such, the portion of the Rx signal within B1Rx passes through the B1Rx portion of the filter63to the corresponding (top) low noise amplifier65and the portion of the Rx signal within B3Rx passes through the B3Rx portion of the filter634to the corresponding (bottom) low noise amplifier65. In the illustrated embodiment, a multiplexer connected to the low noise amplifiers65can combine the signals into a single Rx output, which can be communicated from the module60to a transceiver (not shown) for subsequent downconversion and a baseband processor (not shown) for baseband processing. The transmit Tx path can transmit a transmit radio frequency Tx signal to at least one antenna (not shown). The transmit Tx path is further configured for passage of a Tx signal selectively through either the B1Tx filter or the B3Tx filter of the bandpass filter63, depending on the state of the band select switch62. The band select switch62can include a tunable termination impedance67via which at least one of the B1Tx or B3Tx portions of the filter63can be terminated. For example, in the illustrated embodiment, the switch62is configured for B3Tx transmission, such that the B1Tx portion of the filter63is connected to the tunable termination impedance67, and the B3Tx portion of the filter63is connected to the power amplifier61. Depending on the embodiment, the switch can be configured for B1Tx transmission to alternatively couple the B1Tx portion of the filter63to the power amplifier61and couple the B3Tx portion of the filter63to the tunable termination impedance67. In other embodiments, the switch62permanently connects the B1Tx portion of the filter63to the tunable termination impedance67. For example, a controller (not shown) of the front end module60can be configured to output a signal coupled to the tunable termination impedance67to adjust an impedance of the tunable termination impedance67.

The power amplifier61is configured to amplify the Tx signal. Furthermore, the power amplifier61includes an output having a first output impedance. The power amplifier61may receive the Tx signal from a transceiver (not shown) at an input of the power amplifier61.

In the switched configuration shown inFIG.5, the band select switch62routes a B3Tx signal in band B3, for instance, from the output of the power amplifier61through the B3Tx portion of the filter63to the antenna switch module64for transmission. The B1Tx portion of the filter63can have a passband that spans some or all of a transmit band of an aggressor transmit signal Tx2, such as another transmit channel of the module60. Thus, noise from the aggressor transmit signal Tx2can pass through the B1Tx portion of the filter to the tunable termination impedance67. In this manner, the tunable termination impedance67can be tuned to reduce RIMD resulting from the aggressor transmit signal Tx2.

The illustrated band-select switch62implements a double pole multi throw (DPMT) functionality, the quantity M being an integer greater than 1, one pole of the double pole in communication with the power amplifier61, the other pole of the double pole in communication with the tunable termination impedance67and at least one of the M throws in communication with the filter63.

Optionally, the B1Tx, B3Tx, B1Rx, and/or B3Rx portions of the filter63can be implemented using dual surface acoustic wave (dual-SAW) mode low power filters or other acoustic wave devices, such as other filters incorporating surface acoustic wave (SAW) resonator(s) and/or bulk acoustic wave (BAW) resonators. For example, in one embodiment, the filter portion B1Tx is permanently connected to the tunable termination impedance67, and therefore does not transmit data, and comprises a dual-SAW mode filter or another low power SAW or BAW device.

Typically, a duplexer filter is a three-port circuit element comprising transmitter port, a receiver port, and an antenna port. An RF signal supplied to the transmitter port at the transmit frequency sees the signal path towards the receiver port as a high impedance, so that the radio power is not substantially directed to the receiver port, but it is directed through the antenna port to the antenna, where it is radiated as a RF signal to the environment. Correspondingly, an RF signal received through the antenna and the antenna port at the receive frequency sees the transmitter port as a high impedance, so that it is directed to the receiver port and further to the receiver sections of the radio device. The function of the duplexer filter is generally based on different frequency response characteristics of the filter components. Further combinations of these Tx and Rx bands can be logically extended to gang multiple Tx and Rx filters together toward a single antenna port as well. For example, the multiple frequency bands include bands B1and B3associated with a 3GPP communication standard.

In some implementations, any of the duplexers (or the modules including a duplexer) disclosed herein can include power amplifiers or other components. For example, the duplexer can be implemented as a power amplifier with integrated duplexer (PAiD). Any of the modules or duplexers disclosed herein can be implemented as a PAiD.

The tunable termination impedance67is configured to adjust a critical complex phase of the impedance. The tunable termination impedance67can be configured to be band-specific, in particular to be channel-specific. The tunable termination impedance67can be coupled to the switch62and ground.

The directional coupler66is implemented along the Tx path and configured to extract a portion of the power from the Tx signal, e.g., for monitoring/measurement. In particular, the illustrated directional coupler66is implemented between the power amplifier61and the post-PA switch62.

The antenna switch module64is coupled to the bandpass filter63. Furthermore, the antenna switch module64is configured to connect at least on antenna to the bandpass filter63.

Hence, the proposed invention provides a termination through a filter, e.g., the B1Tx portion of the filter63, in the frequency range of a transmit aggressor Tx2, which is out of band of one or more receive channels, with either a 50 Ohm, or tunable complex impedance that can effectively adjust the critical complex phase of the impedance presented to the transmit aggressor signal Tx2.

Advantageously, the radio frequency module60can optimize emissions/IMS/RxDeSense performance by adjusting the critical complex phase of the impedance for minimization of the IMD. Moreover, the tunable termination impedance67can be used to optimize the IMD performance of the overall path, and uniquely enable higher power for both Tx1and Tx2with acceptable IMD and emissions to support much larger coverage area for the UL-limited EN-DC/UL CA use case.

FIG.6illustrates a schematic diagram of another example of a radio frequency module. In particular, the radio frequency module is configured as a Rx-only diversity receive (DRx) module. The module includes a filter63having four filters that are ganged together, including a B3Rx portion having a passband spanning B3Rx, a BlRx portion having a passband spanning B1Rx, a B1Tx portion having a passband spanning B1Tx, and a B3Tx portion having a passband spanning B3Tx. While the filter portions B1Tx and B3Tx span transmit passbands, the filter portions B1Tx and B3Tx are not used to transmit data. Rather, the filter portions B1Tx and B3Tx are connected to respective tunable termination impedances67to allow for reduction of RIMD caused by by one or more aggressor transmit signals represented by Tx2. For example, the filter portion B1Tx can have a passband that spans some or all of a passband of a transmit aggressor having a first band, whereas the filter portion B3Tx can have a passband that spans some or all of a passband of a transmit aggressor having a second band.

Furthermore, the DRx module comprises two low noise amplifiers65coupled to the B1Rx and B3Rx portions of the filter63, respectively.

The bandpass filter63can be configured as a dual duplexer filter having a first B1duplexer portion comprising the B1Tx and B1Rx filter portions and a second B3duplexer portion comprising the B3Tx and B3Rx filter portions. Alternatively, any band associated with a 3GPP communication standard can be provided. Moreover, the bandpass filter63can be configured to implement more than two duplexers spanning Tx/Rx frequencies of more than two FDD bands.

Thus, a configuration of the radio frequency module as described inFIG.6can minimize the cost of an overhead by large through power in the Rx-only module, when supported with a smaller dual SAW mode low power Rx-style filter. The filter portions B1Tx, B3Tx, B1Rx, and/or B3Rx can comprise dual SAW mode low power filters or other acoustic wave devices, such as other filters incorporating surface acoustic wave (SAW) resonator(s) and/or bulk acoustic wave (BAW) resonators. For instance, because, none of the filter portions B1Tx, B3Tx, B1Rx, B3Rx are used for signal transmission, some or all of these filter portions comprise dual SAW mode filters or other low power SAW or BAW filters. Moreover, the tunable termination impedance67can be used to optimize the IMD performance of the overall path, and uniquely enable higher power for both Tx1and Tx2with acceptable IMD and emissions to support much larger coverage area for the UL-limited EN-DC/UL CA use case.

FIG.7is a schematic diagram of another example of a radio frequency module. The radio frequency module ofFIG.7basically comprises the same features as the radio frequency module ofFIG.6. However, in contrast toFIG.6, the radio frequency module ofFIG.7further comprises a switch68. The switch68can be configured to receive and route the Rx signal from the bandpass filter63to the tunable termination impedance67.

For example, the pre-LNA switch68is configured to include a quad pole four throw (QP4T) functionality, two poles of the quad pole each in communication with a low noise amplifier65, the other two poles of the quad pole each in communication with the tunable termination impedance67and the four throws in communication with the bandpass filter63.

Hence, the DRx module provides an additional Tx bandpass filter in order to properly phase adjust the complex impedance presented in this critical frequency range. Moreover, the tunable termination impedance67can be used to optimize the IMD performance of the overall path, and uniquely enable higher power for both Tx1and Tx2with acceptable IMD and emissions to support much larger coverage area for the UL-limited EN-DC/UL CA use case.

FIG.8depicts an example wireless device800having one or more advantageous features described herein. In the context of a module having one or more features as described herein, such a module can be generally depicted by a dashed box700, and can be implemented as, for example, a front-end module (FEM).

Referring toFIG.8, power amplifiers (PAs)820can receive their respective RF signals from a transceiver810that can be configured and operated in known manners to generate RF signals to be amplified and transmitted, and to process received signals. Similarly, low-noise amplifiers (LNAs)826can receive their respective signals for delivery to the transceiver810. The transceiver810is shown to interact with a baseband sub-system808that is configured to provide conversion between data and/or voice signals suitable for a user and RF signals suitable for the transceiver810. The transceiver810can also be in communication with a power management component806that is configured to manage power for the operation of the wireless device800. Such power management can also control operations of the baseband sub-system808and the module700.

The baseband sub-system808is shown to be connected to a user interface802to facilitate various input and output of voice and/or data provided to and received from the user. The baseband sub-system808can also be connected to a memory804that is configured to store data and/or instructions to facilitate the operation of the wireless device, and/or to provide storage of information for the user.

In the example wireless device800, outputs of the PAs820are shown to be matched (via respective match circuits822) and routed to a duplexer707for routing to a particular antenna816a,816b. The duplexer707can be configured as any of the duplexers described herein. In some embodiments, the duplexer707can include an antenna switch module for routing to a targeted antenna. Additionally or alternatively, an antenna switch module764can be implemented between the duplexer707and the antennas816a,816bfor routing to a targeted antenna. Thereby, the antenna switch module764can be configured as any of the antenna switch modules described herein. Received signals are routed to low-noise amplifiers (LNAs)826through a match circuit824. The duplexer707includes a transmit port701for receiving a transmit RF signal and a receive port702for providing a receive RF signal. The duplexer707also includes a plurality of antenna ports730respectively coupled to the plurality of antennas816a,816b. The duplexer707is configured to route the transmit RF signal from the transmit port701to a first antenna port of the plurality of antenna ports730selected based on an antenna select signal. The duplexer707is also configured to route the receive RF signal to the receive port702from a second antenna port of the plurality of antenna ports730selected based on the antenna select signal. The module also includes a controller840configured to provide the antenna select signal to the duplexer707, as described in greater detail herein.

A number of other wireless device configurations can utilize one or more features described herein. For example, a wireless device does not need to be a multi-band device. In another example, a wireless device can include additional antennas such as diversity antenna, and additional connectivity features such as Wi-Fi, Bluetooth, and GPS.

FIG.9is a schematic diagram of one example of a mobile device900. The mobile device900includes a baseband system901, a transceiver902, a front-end system903, antennas904, a power management system905, a memory906, a user interface907, and a battery908.

The transceiver902generates RF signals for transmission and processes incoming RF signals received from the antennas904.

The front-end system903aids in conditioning signals transmitted to and/or received from the antennas904. In the illustrated embodiment, the front-end system903includes power amplifiers (PAs)911, low noise amplifiers (LNAs)912, filters913, switches914, and duplexers915. However, other implementations are possible.

For example, the front-end system903can provide a number of functionalities, including, but not limited to, amplifying signals for transmission, amplifying received signals, filtering signals, switching between different bands, switching between different power modes, switching between transmission and receiving modes, duplexing of signals, multiplexing of signals (for instance, diplexing or triplexing), or some combination thereof.

The antennas904can include antennas used for a wide variety of types of communications. For example, the antennas904can include antennas for transmitting and/or receiving signals associated with a wide variety of frequencies and communications standards.

The mobile device900can operate with beamforming in certain implementations. For example, the front-end system903can include phase shifters having variable phase controlled by the transceiver902. Additionally, the phase shifters are controlled to provide beam formation and directivity for transmission and/or reception of signals using the antennas904. For example, in the context of signal transmission, the phases of the transmit signals provided to the antennas904are controlled such that radiated signals from the antennas904combine using constructive and destructive interference to generate an aggregate transmit signal exhibiting beam-like qualities with more signal strength propagating in a given direction. In the context of signal reception, the phases are controlled such that more signal energy is received when the signal is arriving to the antennas904from a particular direction. In certain implementations, the antennas904include one or more arrays of antenna elements to enhance beamforming.

The baseband system901is coupled to the user interface907to facilitate processing of various user input and output (I/O), such as voice and data. The baseband system901provides the transceiver902with digital representations of transmit signals, which the transceiver902processes to generate RF signals for transmission. The baseband system901also processes digital representations of received signals provided by the transceiver902. As shown inFIG.9, the baseband system901is coupled to the memory906of facilitate operation of the mobile device900.

The memory906can be used for a wide variety of purposes, such as storing data and/or instructions to facilitate the operation of the mobile device900and/or to provide storage of user information.

The power management system905provides a number of power management functions of the mobile device900. In certain implementations, the power management system905includes a PA supply control circuit that controls the supply voltages of the power amplifiers911. For example, the power management system905can be configured to change the supply voltage(s) provided to one or more of the power amplifiers911to improve efficiency, such as power added efficiency (PAE).

As shown inFIG.9, the power management system905receives a battery voltage from the battery908. The battery908can be any suitable battery for use in the mobile device900, including, for example, a lithium-ion battery.

The front-end system903ofFIG.9can be implemented in accordance with one or more features of the present disclosure. Although the mobile device900illustrates one example of a RF communication device that can include a RFFE system implemented in accordance with the present disclosure, the teachings herein are applicable to a wide variety of RF electronics.

Applications

Some of the embodiments described above have provided examples in connection with wireless devices or mobile phones. However, the principles and advantages of the embodiments can be used for any other systems or apparatus that have needs for front end modules.

Such front end modules can be implemented in various electronic devices. Examples of the electronic devices can include, but are not limited to, consumer electronic products, parts of the consumer electronic products, electronic test equipment, etc. Examples of the electronic devices can also include, but are not limited to, memory chips, memory modules, circuits of optical networks or other communication networks, and disk driver circuits. The consumer electronic products can include, but are not limited to, a mobile phone, a telephone, a television, a computer monitor, a computer, a hand-held computer, a personal digital assistant (PDA), a microwave, a refrigerator, an automobile, a stereo system, a cassette recorder or player, a DVD player, a CD player, a VCR, an MP3 player, a radio, a camcorder, a camera, a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, a multi-functional peripheral device, a wrist watch, a clock, etc. Further, the electronic devices can include unfinished products.

CONCLUSION