Methods related to radio frequency front end systems. In some embodiments, the method can include providing a first module configured to provide multi-input multi-output (MIMO) receive operations for a first plurality of mid bands and a first plurality of high bands. The first module can be further configured to provide transmit operations for the plurality of mid bands. The first module can include a first node. The method can include providing a second module configured to provide transmit and receive operations for a second plurality of mid bands and a second plurality of high bands. The second module can be a power amplifier integrated duplexer (PAiD) module. The second module can include a second node. The first module and the second module can be coupled by a signal path at the first node and the second node, respectively.

A frequency division duplex (FDD) first band includes a first downlink operating band and a first uplink operating band. An FDD second band includes a second downlink operating band and a second uplink operating band. In the FDD first band and the FDD second band, (1) the first downlink operating band, second downlink operating band, first uplink operating band, and second uplink operating band are positioned in order from lowest to highest frequency. The frequency range of the first uplink operating band and that of the second uplink operating band do not overlap each other. A filter is formed in or on a first substrate having piezoelectric properties and has a pass band including the first and second uplink operating bands.

Diplexers and multiplexers for carrier aggregation are disclosed. In one aspect, a front end for receiving carrier aggregation radio frequency signals includes an antenna switch module configured to receive a first radio frequency signal in a first band and a second radio frequency signal in a second band from an antenna, and a diplexer including a first filter configured to pass the first band, a second filter configured to pass the second band, and a diplexed node between the first and second filters and coupled to the antenna switch module. The front end can further include a main amplifier coupled to the diplexed node of the diplexer and configured to amplify radio frequency signals received from the diplexer, and a transconductance stage coupled to the main amplifier and configured to independently control the gain of the main amplifier for the first band and the second band.

Radio frequency (RF) systems with tunable filters are provided herein. In certain embodiments, an RF system includes a first RF processing circuit configured to process a first frequency band of a first communication standard and a second frequency band of a second communication standard. The first frequency band and the second frequency band are close in frequency and/or partially overlapping in frequency. The first RF processing circuit includes a tunable filter for changing the bandwidth of the first RF processing circuit to enhance the robustness of the first RF processing circuit to blocker or jammer signals of a third frequency band.

According to an embodiment, a communication apparatus creates a prediction model taking into consideration of the actual fluctuation of a self-interference signal. The communication apparatus selects, where the self-interference signal has largely fluctuated, a prediction model in accordance with a fluctuation pattern at an early stage of the fluctuation. The communication apparatus generates a cancel signal by control applying a gain and an amount of phase shift represented by the prediction model.

Disclosed is a digital radio-frequency transmitter, which includes a digital logic mixer, a digital power amplifier and an antenna, wherein an output terminal of the digital logic mixer is connected with an input terminal of the digital power amplifier; an output terminal of the digital power amplifier is connected to the antenna; the digital logic mixer is configured to perform logic mixing on baseband data and a radio-frequency local oscillator clock signal which are input into the digital radio-frequency transmitter to generate radio-frequency data; the digital power amplifier is configured to convert the radio-frequency data into an analog power signal; and the antenna is configured to transmit the analog power signal out. According to the digital radio-frequency transmitter of the present application, the circuit layout area and the circuit operation consumption can be effectively reduced.

According to an embodiment, a communication apparatus creates a prediction model taking into consideration of the actual fluctuation of a self-interference signal. The communication apparatus selects, where the self-interference signal has largely fluctuated, a prediction model in accordance with a fluctuation pattern at an early stage of the fluctuation. The communication apparatus generates a cancel signal by control applying a gain and an amount of phase shift represented by the prediction model.

Disclosed is a filter bank die that includes a first acoustic wave (AW) filter having a first antenna terminal coupled to the antenna port terminal and a first filter terminal, wherein the first AW filter is configured to have a filter skirt with a slope that spans at least a 100 MHz gap between adjacent passbands, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter.

Disclosed is a filter bank module having a substrate, an antenna port terminal, and a filter bank die. The filter bank die is fixed to the substrate and includes a first acoustic wave (AW) filter having a first antenna terminal coupled to the antenna port terminal and a first filter terminal, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter.

An access point includes a WiFi chipset, a first radio that is coupled to the WiFi chipset and that is selectively coupled to a first radiating element through one of a first filter or a second filter, and a second radio that is coupled between the WiFi chipset and a second radiating element.