Abstract: Disclosed is a method and a first transceiver of a wireless communication network, for handling reference signals. The method comprises receiving, from a second transceiver, at antenna elements of each of M antenna branches of the first transceiver and in time domain, an OFDM modulated wideband reference signal comprising an OFDM reference signal symbol mapped to every K subcarrier frequency of at least a subset of a carrier frequency bandwidth, and, at each of the M antenna branches, sampling the received wideband reference signal using N samples per OFDM symbol. The method further comprises, for each of the M antenna branches, accumulating the received, sampled wideband reference signal over at least two repetition blocks, each of length of N/K, to obtain a condensed signal with the length N/K samples and conveying the condensed signal over an interface to an aggregate unit.

Abstract: Systems and methods for providing efficient antenna calibration that are particularly beneficial for a radio system having a large antenna array are disclosed.

Abstract: An Advanced Antenna System (AAS) receiver and related methods are provided. According to one aspect an AAS receiver comprises a digital processing block of a Radio Frequency Integrated Circuit (RFIC). The digital processing block comprises an interface for communicating with a Central Unit (CU), and a plurality of Antenna Signal Processing Blocks (ASPBs), each receiving a digitized receive signal from a respective antenna element of an antenna array. Each ASPB comprises one or more receivers, each of which receives the signal from the respective antenna element, processes the received signal, and beamforms the processed signal to produce one or more data streams to be sent to the CU. Each ASPB also includes a narrowband receiver that processes an input signal (either the signal received from the respective antenna element or that signal after processing) to create a narrowband signal that is provided to the CU directly, without beamforming.

Abstract: Systems and methods for providing efficient antenna calibration that are particularly beneficial for a radio system having a large antenna array are disclosed.

Abstract: A base station for detecting a Physical Random Access Channel (PRACH) transmission from a User Equipment device (UE) comprises a radio device and at least one additional device. The radio device comprises narrowband receivers respectively coupled to antenna elements of an antenna array. Each narrowband receiver is configured to receive a signal from a respective antenna element and process the signal to provide received symbols for a PRACH received via the respective antenna element. The radio device also comprises accumulation circuitry configured to, for each antenna element, accumulate a subset of the received symbols for the PRACH received via the antenna element to output a first averaged symbol for the PRACH received via the antenna element. The at least one additional device is configured to receive, from the radio device, the first averaged symbols and process the first averaged symbols to perform PRACH detection for one or more receive beams.

Abstract: A base station for detecting a Physical Random Access Channel (PRACH) transmission from a User Equipment device (UE) comprises a radio device and at least one additional device. The radio device comprises narrowband receivers respectively coupled to antenna elements of an antenna array. Each narrowband receiver is configured to receive a signal from a respective antenna element and process the signal to provide received symbols for a PRACH received via the respective antenna element. The radio device also comprises accumulation circuitry configured to, for each antenna element, accumulate a subset of the received symbols for the PRACH received via the antenna element to output a first averaged symbol for the PRACH received via the antenna element. The at least one additional device is configured to receive, from the radio device, the first averaged symbols and process the first averaged symbols to perform PRACH detection for one or more receive beams.

Abstract: Crest factor reduction techniques and apparatus provide good performance while reducing the impact to power consumption and implementation cost. An example method begins with identifying multiple non-overlapping and separated signal segments in a signal made up of a sequence of digital signal values, each identified segment being an interval in which at least one the digital signal values exceeds a predetermined threshold. For each identified signal segment, an overshoot vector representing the extent by which the identified signal segment exceeds the predetermined threshold is calculated. Each overshoot vector is separately filtered with a digital filter having one or more passbands corresponding to in-band portions of the signal. Each filtered overshoot vector is separately scaled, in some embodiments, and each scaled, filtered, overshoot vector is subtracted from the corresponding portion of the signal, to obtain a compensated signal having a reduced crest factor.

Abstract: An envelope tracking RF transmitter calibration procedure calculates both a supply voltage to apply to a power amplifier for a modulated signal envelope to achieve ISO-gain, and a timing delay adjustment to time-align the applied supply voltage and the modulated signal to minimize distortion due to time delay error. An ISO-gain surface is calculated, as a function of the envelope of a modulated signal and the power amplifier supply voltage, for each of a plurality of desired gain values. As the envelope is swept through a predetermined range of values, demodulated outputs at predetermined points are sampled, and a set of non-linear functions relating the supply voltage to the envelope, which achieve the desired gain at the sampled points, are derived, using surface interpolation between the predetermined gain surface points. Data defining the functions are stored for use during transmitter operation.

Abstract: Crest factor reduction techniques and apparatus provide good performance while reducing the impact to power consumption and implementation cost. An example method begins with identifying multiple non-overlapping and separated signal segments in a signal made up of a sequence of digital signal values, each identified segment being an interval in which at least one the digital signal values exceeds a predetermined threshold. For each identified signal segment, an overshoot vector representing the extent by which the identified signal segment exceeds the predetermined threshold is calculated. Each overshoot vector is separately filtered with a digital filter having one or more passbands corresponding to in-band portions of the signal. Each filtered overshoot vector is separately scaled, in some embodiments, and each scaled, filtered, overshoot vector is subtracted from the corresponding portion of the signal, to obtain a compensated signal having a reduced crest factor.

Abstract: An envelope tracking RF transmitter calibration procedure calculates both a supply voltage to apply to a power amplifier for a modulated signal envelope to achieve ISO-gain, and a timing delay adjustment to time-align the applied supply voltage and the modulated signal to minimize distortion due to time delay error. An ISO-gain surface is calculated, as a function of the envelope of a modulated signal and the power amplifier supply voltage, for each of a plurality of desired gain values. As the envelope is swept through a predetermined range of values, demodulated outputs at predetermined points are sampled, and a set of non-linear functions relating the supply voltage to the envelope, which achieve the desired gain at the sampled points, are derived, using surface interpolation between the predetermined gain surface points. Data defining the functions are stored for use during transmitter operation.

Abstract: The present invention relates to a method of compensating for the phase distortion that occurs in a power amplified output signal in response to the output power of a power amplifier. The invention also relates to a phase distortion compensating device. The device includes a phase-locking and upconversion loop (30-39) which is connected to the input of a power amplifier (40). Briefly, the solution involves feeding a part of the signal (e.sub.pha) to be amplified back to a circuit (35) which combines this first-mentioned signal with a part of the amplified signal (e.sub.out) fed back from the output of the power amplifier (40), so as to achieve a smooth transition in the dominance of one signal over the other signal when the two signals are combined to obtain a new feedback signal (e.sub.fdb) from the combining circuit (35).