Abstract: In one embodiment, an antenna assembly in a cellular network has a radome that houses a plurality of antenna arrays and an electronics module. The electronics module has a weatherproof housing that encloses electronics for processing signals received by and transmitted from a first of the antenna arrays. The electronics module is physically removeably connected to an outer surface of the radome and electrically removeably connected to the first antenna array, such that the electronics module can be removed without (i) disrupting service to other antenna arrays and (ii) removing the antenna assembly from the cell tower on which the antenna assembly is installed.

Abstract: In one embodiment, an antenna assembly in a cellular network has a radome that houses a plurality of antenna arrays and an electronics module. The electronics module has a weatherproof housing that encloses electronics for processing signals received by and transmitted from a first of the antenna arrays. The electronics module is physically removeably connected to an outer surface of the radome and electrically removeably connected to the first antenna array, such that the electronics module can be removed without (i) disrupting service to other antenna arrays and (ii) removing the antenna assembly from the cell tower on which the antenna assembly is installed.

Abstract: In one embodiment, an antenna assembly in a cellular network has a radome that houses a plurality of antenna arrays and an electronics module. The electronics module has a weatherproof housing that encloses electronics for processing signals received by and transmitted from a first of the antenna arrays. The electronics module is physically removeably connected to an outer surface of the radome and electrically removeably connected to the first antenna array, such that the electronics module can be removed without (i) disrupting service to other antenna arrays and (ii) removing the antenna assembly from the cell tower on which the antenna assembly is installed.

Abstract: In one embodiment, an antenna assembly in a cellular network has a radome that houses a plurality of antenna arrays and an electronics module. The electronics module has a weatherproof housing that encloses electronics for processing signals received by and transmitted from a first of the antenna arrays. The electronics module is physically removeably connected to an outer surface of the radome and electrically removeably connected to the first antenna array, such that the electronics module can be removed without (i) disrupting service to other antenna arrays and (ii) removing the antenna assembly from the cell tower on which the antenna assembly is installed.

Abstract: An input signal is pre-distorted to reduce distortion resulting from subsequent signal amplification. Frequency-dependent pre-distortion is preferably implemented in combination with frequency-independent pre-distortion, where the frequency-dependent pre-distortion is generated by expanding the derivative of a product of a pre-distortion function and the input signal and then relaxing constraints on the pre-distortion function and/or on frequency-dependent filtering associated with the frequency-dependent pre-distortion. In one implementation, four different frequency-dependent pre-distortion signals are generated for the expansion using up to four different pre-distortion functions and up to four different frequency-dependent filters.

Abstract: A non-linear power amplifier generates an amplified output signal based on a pre-distorted signal generated by a digital pre-distorter (DPD) based on an input signal. A feedback path generates a feedback signal based on the amplified output signal. The feedback signal is aligned with the input signal, or vice versa, and the aligned signals are used to adaptively update the DPD processing. In particular, a linear FIR filter is estimated to minimize a cost function based on the input and feedback signals. Depending on how the filter is generated, the filter is applied to the input signal or to the feedback signal to generate the aligned input and feedback signals.

Abstract: A non-linear amplifier is linearized using interpolation-based digital pre-distortion (DPD). In one embodiment, the digital input signal is interpolated to generate a higher-sample-rate signal that is then pre-distorted. The resulting higher-sample-rate pre-distorted signal is then decimated to generate a final pre-distorted digital signal that is converted into an analog pre-distorted signal by a digital-to-analog converter (DAC) before being applied to the amplifier. In a polyphase embodiment, different versions of the original input digital signal are generated, where each version is then pre-distorted using a different DPD module to generate a different intermediate pre-distorted digital signal. The intermediate pre-distorted signals are filtered and combined to generate the final pre-distorted digital signal. In both embodiments, better linearization (e.g.

Abstract: A non-linear power amplifier generates an amplified output signal based on a pre-distorted signal generated by a digital pre-distorter (DPD) based on an input signal. A feedback path generates a feedback signal based on the amplified output signal. The feedback signal is aligned with the input signal, or vice versa, and the aligned signals are used to adaptively update the DPD processing. In particular, a linear FIR filter is estimated to minimize a cost function based on the input and feedback signals. Depending on how the filter is generated, the filter is applied to the input signal or to the feedback signal to generate the aligned input and feedback signals.

Abstract: A non-linear amplifier is linearized using interpolation-based digital pre-distortion (DPD). In one embodiment, the digital input signal is interpolated to generate a higher-sample-rate signal that is then pre-distorted. The resulting higher-sample-rate pre-distorted signal is then decimated to generate a final pre-distorted digital signal that is converted into an analog pre-distorted signal by a digital-to-analog converter (DAC) before being applied to the amplifier. In a polyphase embodiment, different versions of the original input digital signal are generated, where each version is then pre-distorted using a different DPD module to generate a different intermediate pre-distorted digital signal. The intermediate pre-distorted signals are filtered and combined to generate the final pre-distorted digital signal. In both embodiments, better linearization (e.g.

Abstract: An input signal is pre-distorted to reduce distortion resulting from subsequent signal amplification. Frequency-dependent pre-distortion is preferably implemented in combination with frequency-independent pre-distortion, where the frequency-dependent pre-distortion is generated by expanding the derivative of a product of a pre-distortion function and the input signal and then relaxing constraints on the pre-distortion function and/or on frequency-dependent filtering associated with the frequency-dependent pre-distortion. In one implementation, four different frequency-dependent pre-distortion signals are generated for the expansion using up to four different pre-distortion functions and up to four different frequency-dependent filters.

Abstract: A system for wireless communications includes a tower structure supporting at least one transmit antenna at an elevated position on the tower structure and base electronics positioned proximate a base of the tower structure. The base electronics are coupled with the transmit antenna and include an initial stage amplifier for amplifying an input signal to provide a low power transmission signal that is provided to the transmit antenna at the elevated position. A final stage amplifier is positioned proximate the transmit antenna. The final stage amplifier is a high efficiency amplifier for efficiently amplifying the low power transmission signal from the base electronics to provide a high power transmission signal to be transmitted from the transmit antenna.

Abstract: An uncorrelated adaptive predistorer configured for use with an RF power amplifier having an input loop configured to be coupled to the input of the RF power amplifier an output loop coupled to the output of the RF power amplifier. Such an input loop includes a look-up table containing predistortion values to be apply to an input signal, in response to a monotonically increasing function of the input signal power, for forming a predistorted input signal. Such an output loop configured to measure an intermodulation distortion product of the RF power amplifier output resulting from the predistorted input signal, and operable to update the predistortion values in the look-up table.

Abstract: A system for wireless communications includes a tower structure supporting at least one transmit antenna at an elevated position on the tower structure and base electronics positioned proximate a base of the tower structure. The base electronics are coupled with the transmit antenna and include an initial stage amplifier for amplifying an input signal to provide a low power transmission signal that is provided to the transmit antenna at the elevated position. A final stage amplifier is positioned proximate the transmit antenna. The final stage amplifier is a high efficiency amplifier for efficiently amplifying the low power transmission signal from the base electronics to provide a high power transmission signal to be transmitted from the transmit antenna.

Abstract: An input signal having amplitude information is pre-distorted and converted into two pre-distorted signals without amplitude information. The two pre-distorted signals are separately amplified and then recombined to generate a linearized amplified output signal having amplitude information. The pre-distortion and conversion may be implemented using a pre-distorter and a LINC modulator. Alternatively, the pre-distortion and conversion may be implemented in circuitry that combines the functions of a pre-distorter and a LINC modulator. The amplified, pre-distorted signals are preferably combined using circuitry that provides at least some impedance matching, such as a transformer or a transmission line tee with transmission line stubs.

Abstract: A pre-distorter pre-distorts an input signal prior to being applied to an amplifier in order to reduce spurious emissions in the resulting amplified signal. The pre-distorter implements an inverted version of a model of the amplifier that models both the frequency independent (FI) characteristics of the amplifier as well as the frequency-independent (FD) characteristics of the amplifier. Techniques and architectures are presented for (1) generating and updating the model, (2) inverting the model, and (3) updating the inverted model.

Abstract: The signal generated by a high-power amplifier (HPA) operating in its non-linear region is linearized by an amplifier circuit using feed-forward compensation in which an auxiliary channel relies on a model of the HPA to generate an auxiliary signal that is combined with the HPA output to generate an amplified linearized output signal. The amplifier circuit may be implemented with a pre-distorter in the main amplifier channel to linearize the HPA using both pre-compensation and feed-forward compensation. Using the HPA model in the auxiliary channel enables the auxiliary signal to be generated without directly relying on the HPA output. This enables the amplifier circuit to be implemented without having to delay the high-power HPA output signal prior to being synchronously combined with the auxiliary signal. In preferred embodiments, the auxiliary channel signal is generated using a relatively low-power amplifier operating in its linear region.

Abstract: An uncorrelated adaptive predistorer configured for use with an RF power amplifier having an input loop configured to be coupled to the input of the RF power amplifier an output loop coupled to the output of the RF power amplifier. Such an input loop includes a look-up table containing predistortion values to be apply to an input signal, in response to a monotonically increasing function of the input signal power, for forming a predistorted input signal. Such an output loop configured to measure an intermodulation distortion product of the RF power amplifier output resulting from the predistorted input signal, and operable to update the predistortion values in the look-up table.

Abstract: The signal generated by a high-power amplifier (HPA) operating in its non-linear region is linearized by an amplifier circuit using feed-forward compensation in which an auxiliary channel relies on a model of the HPA to generate an auxiliary signal that is combined with the HPA output to generate an amplified linearized output signal. The amplifier circuit may be implemented with a pre-distorter in the main amplifier channel to linearize the HPA using both pre-compensation and feed-forward compensation. Using the HPA model in the auxiliary channel enables the auxiliary signal to be generated without directly relying on the HPA output. This enables the amplifier circuit to be implemented without having to delay the high-power HPA output signal prior to being synchronously combined with the auxiliary signal. In preferred embodiments, the auxiliary channel signal is generated using a relatively low-power amplifier operating in its linear region.

Abstract: An input signal having amplitude information is pre-distorted and converted into two pre-distorted signals without amplitude information. The two pre-distorted signals are separately amplified and then recombined to generate a linearized amplified output signal having amplitude information. The pre-distortion and conversion may be implemented using a pre-distorter and a LINC modulator. Alternatively, the pre-distortion and conversion may be implemented in circuitry that combines the functions of a pre-distorter and a LINC modulator. The amplified, pre-distorted signals are preferably combined using circuitry that provides at least some impedance matching, such as a transformer or a transmission line tee with transmission line stubs.