The present description concerns a communication device including a first communication circuit coupled to a first antenna port of the communication device; a switch having first, second and third terminals, the first terminal being coupled to a second antenna port of the communication device, the switch being configured to switch between a first state in which the first terminal is coupled t the second terminal and a second state in which the first terminal is coupled to the third terminal; a third port coupled to the second terminal of the switch; and a second communication circuit coupled to the third terminal.

A method of sparse digital cancellation of receiver nonlinear distortion in carrier aggregation systems is proposed. A reference signal generator generates possible candidate reference signals to be included in a dictionary matrix D. A sparsity-based solution is then applied to dynamically select reference signals based on the RF transceiver configuration. Based on the auto-correlation and cross-correlation with an observed radio signal, a subset of reference signals is selected from the dictionary matrix to match the distortion signal. The number of selected reference signals is flexibly determined based on the design constraints on complexity and power consumption. A greedy sparse estimation approaches, e.g., Orthogonal Matching Pursuit (OMP) can be used for reference signal selection. The reference signal selection is dynamic and adapts itself for different channel responses through correlating the observed radio signal with the dictionary reference signals.

A radio frequency circuit includes a first transfer circuit including a first filter and a second filter, and a second transfer circuit including a third filter and a fourth filter. Passbands of the first filter and the third filter at least partially overlap each other. Passbands of the second filter and the fourth filter at least partially overlap each other. The first filter transfers a radio frequency signal of a first communication system. The third filter transfers a radio frequency signal of a second communication system. The second filter transfers one of a radio frequency signal of the first communication system or a radio frequency signal of the second communication system. The fourth filter transfers the other of a radio frequency signal of the first communication system or a radio frequency signal of the second communication system.

A multimode wireless communication terminal that communicates using a first radio access technology (RAT) and a second RAT determines whether the first and second RATs are in an active state, and modifies a maximum transmit power limit of the first RAT based on a voice codec rate of a voice transmission on the second RAT when the first RAT and the second RAT are in the active state concurrently, wherein the second RAT is conducting the voice transmission in the active state. In an alternative embodiment, the limit is modified based on a transmit power status of the second RAT or on a transmission type of the first RAT.

In a switching circuit, an inductance of an inductor of a shunt circuit is such that off capacitance of a second switching device that is in the off state when a first switching device is in the on state is used to define, in the shunt circuit, a series resonance circuit with a desired resonant frequency. Therefore, the frequency of an unnecessary signal to be attenuated is set to the resonant frequency of the series resonance circuit. Thus, the switching circuit achieves improved isolation characteristics with other circuits by attenuating the unnecessary signal.

A user equipment and a communication method are provided. The user equipment includes a signal transceiver, a first antenna, a second antenna, a third antenna, and a power amplifier module. The signal transceiver applies a conversion between a baseband signal and a radio frequency signal. The first antenna is a primary antenna for receiving and transmitting RF signals. The second antenna is a diversity antenna for receiving RF signals. The third antenna is a low frequency antenna for transmitting signals in a specific low frequency band. The power amplifier module is electrically connected to the signal transceiver, the first antenna, and the third antenna. The power amplifier module amplifies the RF signal output by the signal transceiver and outputs same to either the first or third antenna.

A front-end circuit includes an antenna terminal, front-end terminals (Pfe1, Pfe2), a circulator, and frequency-variable filters. The circulator sends transmission signals of communication bands of a frequency division duplex system and a time division duplex system from the front-end terminal (Pfe1) to the antenna terminal. The circulator sends a reception signal from the antenna terminal to the front-end terminal (Pfe2). The frequency-variable filter is connected between the front-end terminal (Pfe1) and the circulator, passes transmission signals of the frequency division duplex system and the time division duplex system, and attenuates signals other than the above transmission signals. The frequency-variable filter is connected between the circulator and the front-end terminal (Pfe2), passes a reception signal of the frequency division duplex system, and attenuates signals other than the above reception signal.

Filter circuitry is used in communication systems that employ multiple antennas. In general, a communication system may have a transmit path and a receive path. The transmit path extends to a first antenna port and is configured to present signals for transmission in a first communication band and a second communication band to the first antenna port for transmission via a first antenna that is coupled to the first antenna port. The receive path extends to a second antenna port and comprises a first multiple passband/multiple stopband filter that provides a plurality of passbands and a plurality of stopbands interleaved with one another, wherein a first stopband and a second stopband of the plurality of stopbands correspond respectively to the first communication band and the second communication band and are separated by a first passband of the plurality of passbands.

A method and apparatus for receiving and processing multiple carriers with multiple antennas. The device includes a plurality of antennas for receiving signals over a plurality of carriers, and a plurality of receive chains connected to each antenna for processing a signal received on each antenna. The signal received on each antenna is split into multiple receive chains for receive processing. The antennas are grouped into a plurality of sub-groups and a signal on a first carrier is received on a first sub-group of antennas and a signal on a second carrier is received on a second sub-group of antennas. A signal on a third carrier may be received on all antennas. Multiple-input multiple-output (MIMO) on the first and second carriers may be implemented using the first and second sub-group of antennas, respectively, and MIMO on the third carrier may be implemented using all antennas.

The disclosure concerns a signal aggregator component designed to couple with an antenna element to form an antenna system, wherein the resulting antenna system can achieve one-hundred percent or greater efficiency in receiving mode. In addition, the antenna system can achieve specific polarization and gain in different sectors of the antenna radiation pattern. The signal aggregator functions to dynamically enable or disable any number of its RF ports to select the RF input signal to aggregate.