Lucent Technologies Inc.

Andrew Corporation

Christopher F Zappala

Josef Ocenasek

John Stanley Rucki

Michael Anthony Lynch

George Philip Vella-Coleiro

Arild T Kolsrud

Robert C Fairfield

Jack Chi-Chieh Wen

Kevin Loughran

Jack C Wen

Dennis M Cleary

Carmine James Pagano, Ii

William A Nitz

Philip J Hubbauer

Peter Giannoglou

Hayim Vitali Penso

Michael Ralph Simmons

Steven C Andry

Jeffrey G Strahler

In one embodiment, an amplifier system has a tap, a delay filter, a linearized amplifier, and a hybrid combiner. The tapped portion of an input signal is amplified by the amplifier, the untapped portion of the input signal is delayed by the delay filter, and the combiner combines the resulting amplified, tapped portion and the delayed, untapped portion to generate an amplified output signal. By re-combining the delayed, untapped portion of the input signal with the amplified, tapped portion, the power of the untapped portion is not lost, and the amplifier does not have to compensate for all of the distortion that would otherwise be associated with the total output power level. Such an amplifier system is applicable, for example, in upgrading an existing GSM cell site to support both GSM communications as well as UMTS communications without degrading GSM operations.

Amplifier system for cell sites and other suitable applications

A received analog spread-spectrum signal is selectively attenuated prior to digitization, where the amount of attenuation is based on the amplitude of the digitized signal before the digitized signal is filtered to compensate for interference that may exist in the received signal. By selectively attenuating the signal only when the digitized signal is relatively large, the receiver can be implemented using a relatively small analog-to-digital converter (ADC) than would otherwise be the case for a particular signal processing application. Taking advantage of the signal-concentration characteristics of spread-spectrum receivers, embodiments of the present invention can be designed to operate with signal having negative signal-to-noise ratios at the A/D conversion step.

Spread-spectrum receivers with extended dynamic range

A power amplifier's complex pre-distortion curve is generated by decomposing a representation of an input signal, processing the resulting decomposed signals using analog techniques, and performing signal re-composition. In one implementation, two different halves of a transfer function corresponding to the amplitude characteristics of the amplifier are separately modeled and then combined to generate a control signal used to control a voltage-controlled attenuator that attenuates the input signal, while two different halves of a transfer function corresponding to the amplifier's phase characteristics are separately modeled and then combined to generate a different control signal used to control a voltage-controlled phase shifter that adjusts the phase of the input signal. The resulting output signal corresponds to an amplitude-and-phase pre-distorted signal that can be applied to linearize a corresponding (high power) amplifier.

Amplifier linearization by pre-distorting a decomposed input signal

An amplifier distortion reduction system detects a plurality of amplitudes corresponding in time within a frequency band of operation. In response to at least one of the plurality of amplitudes, adjustments can be made to components within the frequency band of operation, enabling the amplifier distortion reduction system to adapt to changing operating conditions. In a feed forward embodiment having a carrier cancellation loop and IMD cancellation or distortion cancellation loop, the output of the carrier cancellation loop can be monitored and equalizer adjustments provided to reduce the amplitude of the carrier signal(s) equally over the frequency band of operation. The output of the IMD cancellation loop can be monitored and equalizer adjustments provided to reduce the IMD components equally over the frequency band of operation. Thus, processing circuitry can monitor amplitudes corresponding in time over the frequency band of operation and provide improved performance over the frequency band.

System and method for producing an amplified signal using plurality of amplitudes across spectrum

A technique for achieving receive diversity without multiple antennas per cell is disclosed. An illustrative embodiment of the present invention comprises: a first antenna for receiving a first information-bearing signal at a first radio frequency; a first downconverter for downconverting the first information-bearing signal to a first intermediate frequency; a first transmitter for transmitting the first information-bearing signal at the first intermediate frequency over a first wireline; means for receiving the first information-bearing signal at the first intermediate frequency from the first wireline and for demodulating the first information-bearing signal.

Wireless telecommunications system architecture supporting receive diversity

The high-power selective signal attenuator includes an attenuator attenuating analog main signals, and a first analog-to-digital converter converting output of the attenuator to digital. A digital-to-analog converter reconverts the digital output of the first ADC to analog, and a cancellor receives the main signals and the analog output from the DAC. The cancellor cancels the analog output of the DAC from the main signals to substantially eliminate high-power signals. A second ADC receives the output of the cancellor and generates a digital output. Based on the digital output, control circuitry dynamically controls the attenuation of the attenuator to prevent saturation of the second ADC and to improve information throughput.

High-power selective signal attenuator and method of attenuation

A predistortion system uses a pilot signal to determine a predistortion function which is used to produce amplitude and/or phase adjustment(s) of an input signal on a signal path. Rather than simply detecting the input signal envelope before and after distortion generating circuitry, such as an amplifier, a pilot signal is provided on the signal path prior to the distortion generating circuitry. After the distortion generating circuitry, the pilot signal is detected. The predistortion system can determine the predistortion function by using the generated pilot signal and the detected pilot signal, for example, to provide improved characterization of the amplifier amplitude and/or phase response or to directly improve the determination of the predistortion function. In certain embodiments, the predistortion function is implemented using a look-up table to produce the amplitude and/or phase adjustment values, and the pilot signal is produced on the signal path by adding the pilot signal to the amplitude and/or phase adjustment values of the look-up table.

Predistortion system and method using a pilot signal

A multi-layer backplane for processing radio frequency (RF) and other signals has alternating layers of conductive traces for RF signals and other types of signals, and ground plane layers of conductive material electrically insulated from each other. The backplane upper layer has a plurality of coaxial connectors for connection of cables and other devices which supply RF energy signals to and convey them from the backplane, with each connector having a center pin extending into the backplane to make electrical contact with a trace of a selected trace layer. A ground plane cap layer of electrically conductive material is provided below the last ground plane layer associated with a trace layer and beneath the coaxial connector center pins for preventing leakage of radio frequency energy between the center pins. A row of conductive vias can be provided along one or more sides of a trace carrying RF energy. These vias are connected to electrical ground references above and below the layer of the trace to electrically isolate the trace from radiating the RF energy. Portions of transition conductive vias and plated-through holes for the connector center pins are removed to adjust to the impedance of components and cables to which they are to be connected.

Backplane for radio frequency signals

An RF filter for a cellular radio receiver whose architecture includes a combination of signal circulators and bandpass filters which operate to selectively notch out sub-bands of the two cellular bands of the cellular radio transmission spectrum so that the sub-bands of both cellular bands can be separately directed to a radio capable of receiving either or both the A or B-band signals. In its preferred form, the architecture of the filter includes two circulators, three bandpass filters having mutually different bandpass characteristics, covering selected portions of the A and B band and a diplexor.

RF filter architecture supporting simultaneous filtered reception of A and B bands of the cellular radio frequency spectrum

An improved CDMA base station for insuring a constant supply of energy to each of a plurality of rake fingers, thus improving gain. One aspect of the base station includes a plurality of pairs of diversity antennas. The energy from the first antenna of each pair is subjected to a delay while the energy from the second antenna of each pair is not subjected to a delay. The added delay is greater than the chip time of the rake fingers. The signals from each pair of antennas is combined and converted to digital form. The energy from all the antennas is then routed to the rake fingers, with the energy from each antenna being routed to one of the rake fingers. The energy from the rake fingers is then combined into a single data stream. In an alternative approach, the base station includes a plurality of diversity antennas. The energy from each of the diversity antennas is subjected to a different amount of delay. The delay difference must again be greater than the chip time of the rake fingers. The energy from the antennas is combined, converted to digital format, and routed to each of a plurality of rake fingers, with the energy from each antenna being routed to the rake finger. The energy from the rake fingers is then combined into a single output data stream.

Methods and apparatus for increasing the uplink gain for a CDMA base station

A wireless telecommunications system architecture is disclosed that is capable of supporting a centralized block radio architecture and of distributing the information-bearing signals from the block radio to geographically-dispersed radio heads using relatively low-cost cable (e.g., twisted-pair, etc.). In accordance with the illustrative embodiment of the present invention, a radio multiplexes, modulates, and channel codes one or more information-bearing signals and upconverts them, not to radio frequency, but to an intermediate frequency that can be transmitted over a low-cost cable. Co-located with each radio head is an upconverter that upconverts the intermediate frequency signal to radio frequency in preparation for radiation by an antenna.

Wireless telecommunications system architecture supporting block radio technology

A wireless base station has a transmitter and receiver. Transmission signals are applied to an antenna through a transmit bandpass filter that is tuned for a transmit band of frequencies. Received signals from the antenna are applied to the receiver through a receive bandpass filter that is tuned for a receive band of frequencies. An RF switching array consisting of four RF switches interconnects the output of the transmitter and the input of the receiver such that normal, loopback (self-test), and scanning modes can be performed. In the normal mode, the antenna is connected to the transmitter and receiver through the transmit and receive bandpass filters, respectively. The transmit and signal paths are effectively isolated from each other by three serially-connected open switches. In the loopback mode, the transmitter output is connected to the receiver input. In the scanning mode, the antenna is connected to the receiver through the transmit bandpass filter. The same set of interconnects provides for loopback and normal operation as well as the new scanning operation. The use of switches rather than couplers or couplers for the loopback function reduces noise and crosstalk between transmit and receive signal lines and lower losses in these lines.

Growing community of inventors

Annandale, NJ, United States of America

Christopher F Zappala