34 results about "Switched diversity" patented technology

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 and system to switch among a plurality of antennae used for wireless communications. A first embodiment is a method for using at least one quality metric and at least one time variation indicator of at least one quality metric to selectively switch among a plurality of antennae to maintain wireless communications. A second embodiment is a method using at least one quality metric and at least one time derivative slope of at least one quality metric to selectively switch among a plurality of antennae to maintain wireless communications. These embodiments can be applied in several wireless communication applications using multiple antennae including, but not limited to, WiMAX applications.

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.

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.

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 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.

Two important factors for switching antenna in the invention are indicating RSSI value of intensity of received signal and value of error frame. Based on certain standard, using the two values determines which antenna should be selected. If degradation of reliability of received signals is caused by shelter from single antenna, then method for switching to another antenna is utilized to improve quality of received signal. The said method is also can be used for gusty interference to guarantee reliability of received signal. Besides selecting receiving antenna, transmission antenna is also selected. Fine results of receiving and transmitting signals are guaranteed as well as the invention plays action for balancing up loading and down loading transmission, the invention is simple and resultful, saving hardware spending and lowering power consumption.

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.

Methods and apparatus are presented for a digital radio receiver using antenna to receive a signal or signals using at least one other method of diversity. In exemplary embodiments of the present invention, both switched antenna diversity and at least one other method of diversity can be utilized in a digital radio broadcast system. In exemplary embodiments of the present invention the timing of an antenna control signal in a receiver can be synchronized so that switchover to a different receiving antenna can occur between adjacent blocks of data being received from whichever of the other diversity sources is then, on average, providing the better reception. For digitally coded transmissions, a clock signal can be provided by a signal processor so as to trigger a diversity controller to switch at an optimum switching time, such as, for example, between groups or “blocks” of digitally encoded information, thus eliminating or minimizing disruption of a contiguous data stream.

A diversity receiver includes first and second reception circuits using a superheterodyne principle. At stationary reception, reception of the audio signals and the data employing a phase diversity reception system is performed such that the signals received by the first reception antenna are supplied to the first reception circuit, the signals received by the second reception antenna are supplied to the second reception circuit, and phases of first and second intermediate-frequency signals are controlled and the first and second intermediate-frequency signals are added. At reception-frequency search, reception of the audio signals employing an antenna-switching diversity reception system is performed such that the signals received by at least one of the first and second antennas are supplied to the first reception circuit and reception of the data and the reception-frequency search are performed, and the signals received by the first and second antennas are supplied to the second reception circuit.

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.

A comparative quality factor may be based on quantities indicative of signal and noise received at multiple antennas and may be used to control switching in a switched diversity system.

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.

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 wireless audio receiver system and method is provided that is capable of receiving one or more radio frequency (RF) signals containing audio signals modulated by analog and / or digital modulation schemes, operating in full diversity mode or switched diversity mode, demodulating the RF signals, and outputting analog audio signals and a combined digital audio signal. The system and method switches multiple diversity antennas to route received RF signals to respective RF signal processing paths. Digitized passband modulated signals are demodulated to generate analog audio signals, and a combined digital audio signal with one or multiple channels may also be generated. The system and method are capable of demodulating signals modulated using a wide variety of modulation schemes. Reconfigurable computing components are utilized to demodulate digitized passband modulated signals and generate the analog audio signals and combined digital audio signal.

The invention provides a method for realizing a second generation telecommunication (2G) / 3G circuit domain calling service in a long term evolution (LTE) packet switched (PS) connection status. The method comprises the steps that a terminal upper layer sends an antenna switching order to an LTE physical layer; when receiving the antenna switching order from the terminal upper layer, the LTE physical layer modifies antenna measurement configuration of downlink Channel quality indicator / Precoding matrix indicator / Rank indicator (CPR) measurement; the LTE physical layer performs downlink CPR measurement under the antenna measurement configuration, and generates a measurement result to be reported to a network side; after receiving updated configuration information for the measurement result from the network side, the LTE physical layer updates receiving configuration, so as to be adapt to a data transmission mode of single antenna receiving; the LTE physical layer receives a signal from the network side through the updated receiving configuration; while the LTE physical layer updates the receiving configuration, the terminal upper layer controls switch of connection modes of a terminal antenna; and a switched diversity receiving antenna initiates the circuit domain calling service in a circuit domain communication network.

The present invention discloses a microwave receiver and multi-antenna switching diversity reception method, and relates to the unmanned aerial vehicle communication field. The method comprises: controlling one end of the antenna switching circuit in a microwave receiver to connect with the nth receiving antenna in N receiving antennas, n is a positive integer and the initial value of the n is 1, receiving a data packet through the nth receiving antenna, calculating the number of consecutive lost datagrams when the nth receiving antenna receives data packets, detecting whether the number of consecutive lost datagrams reaches the threshold of the number of packet loss or not, and if the number of consecutive lost datagrams reaches the threshold of the number of packet loss, defining n=n+1, and repeatedly executing the step of controlling one end of the antenna switching circuit being connected with the nth receiving antenna in the N receiving antennas. The comparison of the number of consecutive lost datagrams and the preset threshold of the number of packet loss is taken as a switching condition, the logic is simple, No extra hardware modules are required, and the system power consumption and the hardware scale are reduced while the multi-path fading and distortion in the multi-path transmission process.

Fading is countered in a WLAN or similar system to maintain QoS by a fusion of switched diversity and protocol based redundancy using time spaced transmission bursts to improve the performance of radio receivers. This redundancy may be enhanced by an overlay of space-time coding of the transmission bursts.

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.