34 results about "Switched diversity" patented technology

A beam-forming system comprises a cooperative array of wireless terminals coupled to at least one wireless wide area network (WWAN) and communicatively coupled to a wireless local area network (WLAN) configured to provide information exchanges between the wireless terminals. A cooperative beam-forming system employing the WLAN provides antenna-array processing benefits (such as frequency reuse, interference rejection, array-processing gain, antenna-switching diversity) to the individual wireless terminals. A network access operator facilitates network control functionality between the WWAN and the cooperative array of wireless terminals.

A method is provided for coherently tracking a radio signal including a plurality of digitally modulated reference subcarriers. The method comprises the steps of receiving symbols transmitted on the reference subcarriers, combining the reference subcarrier symbols with a known reference sequence conjugate to produce a plurality of samples, median filtering the samples to produce filtered samples, and smoothing the samples for each of the reference subcarriers over the plurality of reference subcarriers to produce a coherent reference signal estimate for each of the subcarriers. A receiver for coherently tracking a radio signal including at least one digitally modulated reference carrier is also provided.

A method, antenna switching integrated circuit (IC), and communications device that connect a transmitter to a selected antenna to propagate at least one transmission signal to the selected one of at least two antennas, based on feedback information associated with one or more antennas. An antenna tuning and switching (ATS) controller receives feedback information about a current status of an antenna tuner, wherein the current status of the antenna tuner is either locked or unlocked. In response to the current status of the antenna tuner being in a locked state, the ATS controller triggers an antenna selection switch to connect the antenna (that is associated with the antenna tuner) to the transmitter in order to propagate the transmission signal(s) from the transmitter to the antenna. If the antenna tuner is in an unlocked state, the ATS controller selects a different antenna that is not associated with an antenna tuner.

A diversity apparatus for a mobile communication terminal with a GPS function. The diversity apparatus comprises: a first multiband antenna with a first reception polarization characteristic, for receiving a combined RF signal of a GPS signal and a mobile communication signal; a second multiband antenna with a second reception polarization characteristic distinguished from the first reception polarization characteristic, for receiving a combined RF signal of a GPS signal and a mobile communication signal; and a switching diversity unit for selecting one of the RF signals received by the first and second multiband antennas.

A diversity apparatus for a mobile communication terminal with a GPS function. The diversity apparatus comprises: a first multiband antenna with a first reception polarization characteristic, for receiving a combined RF signal of a GPS signal and a mobile communication signal; a second multiband antenna with a second reception polarization characteristic distinguished from the first reception polarization characteristic, for receiving a combined RF signal of a GPS signal and a mobile communication signal; and a switching diversity unit for selecting one of the RF signals received by the first and second multiband antennas.

Systems and methods are provided for enhancing signal quality at receivers in a wireless network. In one embodiment, an antenna is selected from a subset of antennas based on a signal quality parameter such as received signal power or signal-to-noise ratio (SNR). In another embodiment, multiple antennas are applied to independent signal processing paths for the respective antennas where output from the paths is then combined to enhance overall signal quality at the receiver.

An antenna-switching diversity receiver is capable of switching antennas without bringing about deterioration of reception characteristics even when applied to the CDMA communication method. A TFCI bit decoding / determination unit decodes TFCI bits that have been extracted by a TFCI bit extractor and determines the presence or absence of communication control data based on the TFCI bits that have been decoded. An antenna switching control unit uses a timer to check for the presence or absence of communication control data in each of fixed time intervals based on the determination results of the TFCI bit decoding / determination unit and then controls the antenna switch in intervals that lack communication control data to measure the reception level of the common pilot channel at the other antenna that differs from the antenna that is currently receiving and then select the antenna having the higher reception level.

An antenna-switching diversity receiver is capable of switching antennas without bringing about deterioration of reception characteristics even when applied to the CDMA communication method. A TFCI bit decoding / determination unit decodes TFCI bits that have been extracted by a TFCI bit extractor and determines the presence or absence of communication control data based on the TFCI bits that have been decoded. An antenna switching control unit uses a timer to check for the presence or absence of communication control data in each of fixed time intervals based on the determination results of the TFCI bit decoding / determination unit and then controls the antenna switch in intervals that lack communication control data to measure the reception level of the common pilot channel at the other antenna that differs from the antenna that is currently receiving and then select the antenna having the higher reception level.

An RF receiver system is provided having a plurality of selectable antennas. The system includes a receiver for receiving RF signals from one of the plurality of antennas at a time. The receiver includes processing circuitry for processing the RF signals and generating a control signal to control selection of one of the antennas at a time. The system further includes a switched diversity module having a plurality of switches coupled to the plurality of antennas for selecting one of the antennas at a time. The switched diversity module further includes logic receiving the control signal generated by the receiver and generating logic output signals to control selection of one of the antennas at a time.

Provided are a transmission / receiving apparatus and method of switching a transmission antenna in a Transmission Switched Diversity (TSD) system. The transmission apparatus includes an announcement command frame reading unit to verify a TSD Information Element (IE) included in an announcement command frame when receiving the announcement command frame from a receiving apparatus, and to verify whether to request a switching of the transmission antenna, an antenna switching unit to select an antenna, not being selected from a plurality of antennas, as a transmission antenna when the announcement command frame requests the switching of the transmission antenna, and to switch a currently used antenna into the selected transmission antenna, and an announcement command frame generation unit to convert transmission antenna information included in the TSD IE into the selected transmission antenna, and to generate a response announcement command frame including the converted TSD IE and transmit to the receiving apparatus.

A method for switched diversity, including: determining, on a pair-wise basis, a plurality of comparative quality factors corresponding to at least two antennas based on signals received by the at least two antennas; filtering, over a period of time, multiple instances of at least one of the plurality of comparative quality factors; and selecting at least one of the signals to couple to at least one receiver chain based on the comparative quality factors.

Systems and methods are presented for digital antenna diversity combining. In exemplary embodiments of the present invention, at least two antenna signal paths can be communicably connected to a receiver. Each antenna signal path can be provided with an RF tuner communicably connected to a demodulator, which can estimate the signal to noise ratio (SNR) and time of arrival of its respective antenna signal. In exemplary embodiments of the present invention, a time alignment circuit can be communicably connected to each antenna signal path, and a maximum ratio combiner can be communicably connected to the time alignment circuit. In operation, the time alignment circuit can use the time of arrival estimate to align the multiple signals and the maximum ratio combiner can use the SNR estimate obtained for each antenna signal to respectively weight each signal and thereby generate a combined output signal. In exemplary embodiments of the present invention, a switch diversity combiner can be further provided, and can quickly detect when an antenna signal is entering a fade, allowing the maximum ratio combiner to set that signal's weight to zero. In exemplary embodiments of the present invention, a digital diversity combiner can be provided in a stand alone integrated circuit, or can be integrated in a larger integrated circuit, such as, for example, a satellite radio overlay processor.

A low-cost diversity antenna switching system and method is realized by controlling bias voltages on PIN diodes. By increasing the reverse bias voltage impressed upon a PIN diode, an RF signal impressed upon the diode is increasingly attenuated. As the PIN diode is forward biased to conduct in the forward direction, RF attenuation decreases. Two or more PIN diodes are used to increasingly attenuate signals from one antenna as attenuation of signals from another antenna is gradually decreased. The progression of the bias voltages is accomplished using a microprocessor that monitors a received signal strength indicator (RSSI) signal from a radio receiver. The RSSI is used to control which of two antennas are coupled into the receiver by predicting a signal fade.

Antenna switch diversity circuitry can include four switches. A first switch can be connectable to a first transmitter, a first receiver, and a second receiver. A second switch can be connectable to a second transmitter, a third receiver, and a fourth receiver. A third switch can be directly connected to the first switch, the second switch, a first antenna, and a second antenna. A fourth switch directly can be connected to the first switch, the second switch, a third antenna, and a fourth antenna. The first and second switches can be configured to be controlled by a control signal in a manner so as to prevent a signal from the first transmitter and a signal from the second transmitter from being conveyed through a same switch, which can reduce a production of an intermodulation distortion signal by the signal from the first transmitter and the signal from the second transmitter.

Provided are a transmission / receiving apparatus and method of switching a transmission antenna in a Transmission Switched Diversity (TSD) system. The transmission apparatus includes an announcement command frame reading unit to verify a TSD Information Element (IE) included in an announcement command frame when receiving the announcement command frame from a receiving apparatus, and to verify whether to request a switching of the transmission antenna, an antenna switching unit to select an antenna, not being selected from a plurality of antennas, as a transmission antenna when the announcement command frame requests the switching of the transmission antenna, and to switch a currently used antenna into the selected transmission antenna, and an announcement command frame generation unit to convert transmission antenna information included in the TSD IE into the selected transmission antenna, and to generate a response announcement command frame including the converted TSD IE and transmit to the receiving apparatus.