In one aspect there is provided a method. The method may include receiving a first analog radio frequency signal including a signal of interest and an interference signal caused by a second analog radio frequency signal transmitted in full duplex over a channel from which the first analog transmission is received; combining the first analog radio frequency signal and a portion of the second analog radio frequency signal to generate an output analog radio frequency signal characterized by at least a reduction or an elimination of the interference signal included in the output analog radio frequency signal; and providing the output analog radio frequency signal. Related apparatus, systems, methods, and articles are also described.

Single channel full duplex wireless communications

A wireless communication device includes, in part, an analog interference cancellation circuit and a controller. The analog cancellation circuit includes a multitude of delay paths each including a delay element and a variable attenuator. The controller dynamically varies the attenuation level of each of the variable attenuators in accordance with the frequency response characteristic of that attenuator to remove a portion of a self-interference signal present in a signal received by the device. The device measures the frequency response characteristic of the communication channel, used in determining the attenuation levels, via one or more preamble symbols. A second portion of the self-interference signal is removed by the device using a multitude of samples of a transmitted signal and a multitude of samples of a signal to be transmitted.

Self-interference cancellation

One method of operation includes beamforming a plurality of microphone outputs to obtain a plurality of virtual microphone audio channels. Each virtual microphone audio channel corresponds to a beamform. The virtual microphone audio channels include at least one voice channel (135) and at least one noise channel (136). The method includes performing voice activity detection (151) on the at least one voice channel (135) and adjusting a corresponding voice beamform until voice activity detection (151) indicates that voice is present on the at least one voice channel (135). Another method beamforms the plurality of microphone outputs to obtain a plurality of virtual microphone audio channels, where each virtual microphone audio channel corresponds to a beamform, and with at least one voice channel (135) and at least one noise channel (136). The method performs voice recognition on the at least one voice channel (135) and adjusts the corresponding voice beamform to improve a voice recognition confidence metric (159).

Apparatus and Method for Beamforming to Obtain Voice and Noise Signals

A MIMO wireless communication device includes, in part, a first transmit path adapted to transmit a first transmit signal from a first antenna, a second transmit path adapted to transmit a second transmit signal from a second antenna, a first receive path adapted to receive a first receive signal, an interference cancellation circuit and a controller. The cancellation circuit includes a cascaded filter structure each filter including a multitude of filter taps each including a variable element. The controller dynamically varies a value applied to each of the plurality of variable elements in accordance with frequency response characteristics of the variable element to remove a portion of a self-interference and/or cross-talk interference signal present in a signal received by the device. The device measures the frequency response characteristic of a multitude of communication channels, used in determining the values, via one or more preanible symbols that are jointly transmitted from the first transmit antenna and the second transmit antenna. A second portion of the interference signal is removed by a digital cancellation circuit using a multitude of samples of a transmitted signal.

Self-interference cancellation for mimo radios

A system for hybrid self-interference cancellation includes a transmit coupler that samples an RF transmit signal, a RF self-interference canceller that transforms the sampled RF transmit signal to an RF self-interference cancellation signal, an IF self-interference canceller that transforms a downconverted version of the RF transmit signal to an ISRF self-interference cancellation signal, and a receive coupler that combines the RF and ISRF self-interference cancellation signals with an RF receive signal.

Systems and methods for hybrid self-interference cancellation

The disclosed invention relates to a transceiver system comprising a notch filter element configured to suppress transmitter blockers (i.e., transmitter interferer signals) within a reception path. In some embodiments, the transceiver front-end comprises a differential reception path, having a first differential branch and a second differential branch, configured to provide an RF differential input signal having a transmitter blocker to a transimpedance amplifier, comprising a first-order active filter and a notch filter element. The notch filter element comprises a stop band corresponding to a frequency of a transmitted signal, such that the notch filter element suppresses the transmitted blocker without degrading the signal quality of the received differential input signal.

Second-order filter with notch for use in receivers to effectively suppress the transmitter blockers

A method for searching for a radio cell is provided comprising determining, for each of a plurality of frequencies, a reception strength value indicating the reception strength within a first bandwidth around the frequency, wherein the first bandwidth is smaller than a second bandwidth with which a radio cell to be searched is operated; determining, based on the determined reception strength values, a spectral position for a radio cell at which a cell search is to be carried out; and carrying out a cell search at the determined spectral position.

Method for searching for a radio cell and mobile terminal

Some embodiments of the present disclosure relate to multiband receivers that include at least one divider unit having a divisor that is other-than-two For example, in some embodiments the divisor is an odd integer (eg, three) Such divisors allow oscillators for respective receiver subunits in a multi-band receiver to have frequencies that are sufficiently different from one another so as to limit cross-talk interference there between, even when the receiver subunits are concurrently receiving data on adjacent channels To facilitate this other-than-two divisor, a phase error compensation block is often used to compensate for the effects of using the other-than-two divisor

Communication device including multiple LO receivers

This paper presents a multimode-mode filtering ΔΣ-modulator for receivers with reconfigurable digitally enhanced blocker rejection. The required signal to noise ratio of the signal of interest is typically much lower than the required DR due to also received interfering signals. Therefore, it is of interest to build the ADC in the receiver with a high blocker tolerance, to reduce its required signal to noise ratio and even relax the rest of the receiver chain. For this purpose, a semi-digital implementation of a reconfigurable and frequency selective interferer suppression is proposed. The prototype is designed in a 28nm CMOS technology, occupies an area of 0.089mm2 and achieves 59.4/57.9/50.4dB inband SNDR in a bandwidth of 8.9/18.3/38.3MHz, together with a power consumption of 12.5/14.3/15.6mW. Using the proposed technique, the modulator simultaneously achieves a out-of-band blocker tolerance which is even +18dB beyond full scale.

A multimode CT ΔΣ-modulator with a reconfigurable digital feedback filter for semi-digital blocker/interferer rejection

Es wird ein Verfahren zur Suche nach einer Funkzelle bereitgestellt, das fur jede einer Vielzahl von Frequenzen die Ermittlung eines Empfangsstarkewerts, der auf die Empfangsstarke innerhalb einer ersten Bandbreite um die Frequenz hinweist, worin die erste Bandbreite kleiner als eine zweite Bandbreite ist, bei der eine zu suchende Funkzelle betrieben wird; die Ermittlung auf Grundlage der ermittelten Empfangsstarkewerte einer Spektralposition fur eine Funkzelle, bei der eine Zellsuche durchgefuhrt werden soll; und die Durchfuhrung einer Zellsuche bei der ermittelten Spektralposition umfasst.

Stefan Herzinger

Papers

Second-order filter with notch for use in receivers to effectively suppress the transmitter blockers

Method for searching for a radio cell and mobile terminal

Communication device including multiple LO receivers

A multimode CT ΔΣ-modulator with a reconfigurable digital feedback filter for semi-digital blocker/interferer rejection

Funkzellsuchverfahren und mobiles Endgerät