Systems and methods for randomization of per-element multi-user signal input for decorrelated sub-carrier signals

Abstract

Systems and methods include filtering, using a filter prior to an amplifier, each information- bearing carrier signal of a plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal so as to introduce a delay into each information-bearing carrier signal, the delay of each information-bearing carrier signal being randomly selected, and where the delay of each information-bearing carrier signal is sufficient to reduce correlation between the plurality of information-bearing carrier signals to mitigate a peak-to-average power ratio to below a threshold level. Upon filtering, the plurality of information-bearing carrier signals are amplified in accordance with the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals.

Description

SYSTEMS AND METHODS FOR RANDOMIZATION OF PER-ELEMENT MULTI-USER SIGNAL INPUT FOR DECORRELATED SUB-CARRIER SIGNALSFIELD OF TECHNOLOGY

[0001] The present disclosure generally relates to systems and methods for operating an amplifier in a signaling system at or near saturation while mitigating distortion resulting from high Peak-to-Average Ratio (PAPR), such as by applying randomization to signal inputs in the signaling systems for greater decorrelation of the signal inputs to the amplifier.BACKGROUND OF TECHNOLOGY

[0002] Beamforming is a signal processing technique used in sensor arrays to direct signals in specific directions. For example, by combining elements in an antenna array, it allows signals from certain angles to strengthen (constructive interference) while signals from other angles to weaken (destructive interference). This technique can be applied at both the transmitting and receiving ends to achieve spatial selectivity in signaling systems including Radio Frequency (RF) signaling, optical signaling and / or acoustic signaling, enhancing directivity compared to omnidirectional methods.

[0003] A signaling system can include a transmitter, receiver and / or transceiver. A transmitter includes circuitry for generating and / or transmitting a signal. Some transmitters generate a signal that combines a carrier with a modulation signal through modulation. Modulation can include analog and / or digital modulation. Examples of analog modulation include: Amplitude Modulation (AM) where the information is added to the signal by varying its amplitude including via sideband modulation and / or Quadrature Amplitude Modulation (QAM), Frequency Modulation (FM) transmitter where the information is added by varying the signal's frequency, Phase Modulation (PM) where the information is added to the signal by varying the phase shift of the signal,Transpositional Modulation (TM) where the information is added to the signal by varying waveform inflections.

[0004] Examples of digital modulation include: Amplitude Shift Keying, Frequency Shift Keying, Phase Shift Keying, Quadrature Amplitude Modulation (QAM), among others.

[0005] Frequency-Divisional Modulation (including Orthogonal Frequency-Division Multiplexing) among others or any combination thereof.

[0006] In Amplitude Shift Keying (ASK), each symbol in the message signal gives a unique amplitude to the carrier wave.

[0007] In Frequency Shift Keying (FSK), each symbol in the message signal gives a unique frequency to the carrier wave.

[0008] In Phase Shift Keying (PSK), each symbol in the message signal gives a unique phase shift to the carrier wave.

[0009] In Quadrature Amplitude Modulation (QAM), two digital bit streams are created by modulating the amplitudes of two carrier waves, e.g., using the amplitude-shift keying (ASK) digital modulation scheme or amplitude modulation (AM) analog modulation scheme. The two carrier waves are of the same frequency and are out of phase with each other by 90° (orthogonal), which are then adding together.

[0010] In Orthogonal Frequency-Division Multiplexing (OFDM), which is a frequency-division multiplexing (FDM) scheme where the incoming bitstream representing the data to be sent is divided into multiple closely spaced orthogonal sub-carrier signals with overlapping spectra. The sub-carriers are transmitted, with each sub-carrier modulated with bits from the incoming stream so multiple bits are being transmitted in parallel to increase the information being carried in signals.

[0011] In On-Off Keying On-off keying (OOK) is a form of amplitude- shift keying (ASK) modulation that represents digital data as the presence or absence of a carrier wave.

[0012] Pulse Position Modulation is a modulation technique in which the position of pulse varies according to instantaneous value of amplitude of sampled modulating signal, for example by making a pulse that is directly proportional to amplitude value of a sampled message signal.

[0013] An amplifier can be used to amplify the modulated and / or multiplexed signals for transmission. However, there are limits to the number of signals or the input power an amplifier can amplify at a given time before the amplifier reaches saturation. Amplifier saturation is a phenomenon where the output voltage is limited to a peak value, usually slightly less than the power supply voltage. Saturation occurs when the differential input voltage is too high for the amplifier’s gain, driving the output level to that peak value. The amplifier can have a range of input powers where the amplifier operation is linear such that the output of the amplifier is equal to the input signal plus a gain.

[0014] However, when the input signal reaches sufficient power, the amplifier stops behaving linearly, e.g., the amplifier does not amplify the input signal by the specified gain, and the output of the amplifier starts to saturate and eventually the slope of the Input power vs Output power of the amplifier approaches zero, or in some cases reduces. The power level at which this happens is known as saturated output power. Indeed, where inputs to the amplifier have a wide dynamic variation between the signal’s peak and the average power (the Peak-to-Average Power Ratio), e.g., due to the sum of multiple sinusoidal signals that can exhibit constructive and destructive behavior, the PAPR can become high enough to cause an amplifier to operate in its non-linear region, thus causing distortion such as clipping. Indeed, a high PAPR can cause two problems:first, out-of-band distortion can lead to adjacent-channel interference and spectral emission mask (SEM) violations, and second, in-band distortion can degrade the throughput performance.SUMMARY

[0015] In some aspects, the techniques described herein relate to a method including: obtaining, by at least one signal processing device, a plurality of information-bearing carrier signals associated with a plurality of electronic communications to a plurality of endpoints, each information-bearing carrier signal of the plurality of information-bearing carrier signals having a different phase; filtering, by the at least one signal processing device, using a filter, each information-bearing carrier signal of the plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal of the plurality of information-bearing carrier signals so as to introduce a delay into each information-bearing carrier signal of the plurality of information-bearing carrier signals; wherein the delay of each information -bearing carrier signal of the plurality of information-bearing carrier signals is randomly selected; wherein the delay of each information-bearing carrier signal of the plurality information-bearing carrier signals is sufficient to reduce correlation between the plurality of information-bearing carrier signals to mitigate a peak-to-average power ratio to below a threshold level; and amplifying, by the at least one signal processing device using at least one amplifier, the plurality of information-bearing carrier signals in accordance with the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals.

[0016] In some aspects, the techniques described herein relate to a method, further including: filtering, by the at least one signal processing device, using an inverse filter, upon the amplifying, the plurality of information-bearing carrier signals based at least in part on the phase of each information-bearing carrier signal; wherein the inverse filter is inverse to the filter so as to removethe delay from each information-bearing carrier signal of the plurality of information-bearing carrier signals.

[0017] In some aspects, the techniques described herein relate to a method, wherein the filter is an all pass filter.

[0018] In some aspects, the techniques described herein relate to a method, wherein the filter is a digital filter.

[0019] In some aspects, the techniques described herein relate to a method, wherein splitting the information-bearing carrier signal into a plurality of information-bearing carrier signals includes: utilizing, by the at least one signal processing device, at least one beamformer to beamform the plurality of information -bearing carrier signals; wherein the filter is configured to filter the plurality information-bearing carrier signals after the at least one beamformer.

[0020] In some aspects, the techniques described herein relate to a method, further including: controlling, by the at least one signal processing device, at least one antenna to transmit the plurality of information-bearing carrier signals.

[0021] In some aspects, the techniques described herein relate to a method, wherein the at least one amplifier includes at least one non-linear amplifier.

[0022] In some aspects, the techniques described herein relate to a method, wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals includes at least one half of a symbol in length.

[0023] In some aspects, the techniques described herein relate to a method including: filtering, by the at least one signal processing device, using a filter, each information-bearing carrier signal of a plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal of the plurality of information-bearing carrier signals so as to introduce a delay intoeach information-bearing carrier signal of the plurality of information-bearing carrier signals; wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals is randomly selected; wherein the delay of each information-bearing carrier signal of the plurality information-bearing carrier signals is sufficient to decorrelate the plurality of information-bearing carrier signals; wherein each information-bearing carrier signals includes data associated with an electronic communication; amplifying, by the at least one signal processing device using at least one amplifier, the plurality of information-bearing carrier signals in accordance with the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals; and filtering, by the at least one signal processing device, using an inverse filter, upon the amplifying, the plurality of information-bearing carrier signals based at least in part on the phase of each information -bearing carrier signal; wherein the inverse filter is inverse to the filter so as to remove the delay from each information-bearing carrier signal of the plurality of information-bearing carrier signals.

[0024] In some aspects, the techniques described herein relate to a method, wherein the filter is an all pass filter.

[0025] In some aspects, the techniques described herein relate to a method, wherein the filter is a digital filter.

[0026] In some aspects, the techniques described herein relate to a method, wherein splitting the information-bearing carrier signal into a plurality of information-bearing carrier signals includes: utilizing, by the at least one signal processing device, at least one beamformer to beamform the plurality of information -bearing carrier signals; wherein the filter is configured to filter the plurality information-bearing carrier signals after the at least one beamformer.

[0027] In some aspects, the techniques described herein relate to a method, further including: controlling, by the at least one signal processing device, at least one antenna to transmit the plurality of information-bearing carrier signals.

[0028] In some aspects, the techniques described herein relate to a method, wherein the at least one amplifier includes at least one non-linear amplifier.

[0029] In some aspects, the techniques described herein relate to a method, wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals includes at least one half of a symbol in length.

[0030] In some aspects, the techniques described herein relate to a signal processing apparatus including: at least one filter configured to filter each information-bearing carrier signal of a plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal of the plurality of information-bearing carrier signals so as to introduce a delay into each information-bearing carrier signal of the plurality of information-bearing carrier signals; wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals is randomly selected; wherein the delay of each information-bearing carrier signal of the plurality information-bearing carrier signals is sufficient to decorrelate the plurality of information-bearing carrier signals; wherein each information-bearing carrier signals includes data associated with an electronic communication; at least one amplifier configured to amplify the plurality of information-bearing carrier signals in accordance with the delay of each informationbearing carrier signal of the plurality of information-bearing carrier signals; and at least one inverse filter configured to, upon the amplifying, the plurality of information-bearing carrier signals based at least in part on the phase of each information-bearing carrier signal; wherein the inverse filter isinverse to the filter so as to remove the delay from each information-bearing carrier signal of the plurality of information-bearing carrier signals.

[0031] In some aspects, the techniques described herein relate to a signal processing apparatus, wherein the filter is an all pass filter.

[0032] In some aspects, the techniques described herein relate to a signal processing apparatus, further including at least one beamformer configured to beamform the plurality of informationbearing carrier signals prior to the at least one filter.

[0033] In some aspects, the techniques described herein relate to a signal processing apparatus, further including at least one antenna configured to transmit the plurality of information-bearing carrier signals.

[0034] In some aspects, the techniques described herein relate to a signal processing apparatus, wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals includes at least one half of a symbol in length.BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Various embodiments of the present disclosure can be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present disclosure. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ one or more illustrative embodiments.

[0036] FIG. 1A depicts a block diagram of beamforming transmitting circuitry utilizing randomized delays in accordance with one or more embodiments of the present disclosure.

[0037] FIG. IB illustrates a spectral waveform of three signals in accordance with one or more embodiments of the present disclosure.

[0038] FIG. 1C illustrates impulses of the frequency domain of the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0039] FIG. ID depicts a pole-zero diagram for the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0040] FIG. IE depicts a magnitude response for the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0041] FIG. IF depicts phase response the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0042] FIG. 1G depicts phase response (unwrapped) for the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0043] FIG. 1H illustrates group delay of the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0044] FIG. II depicts an output y(n) from the group delay of three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0045] FIG. 2 depicts another block diagram of beamforming transmitting circuitry utilizing randomized delays in accordance with one or more embodiments of the present disclosure.

[0046] FIG. 3 depicts another block diagram of beamforming transmitting circuitry utilizing randomized delays in accordance with one or more embodiments of the present disclosure.

[0047] FIG. 4 depicts exemplary average correlation coefficients (over all M elements, for M = 8 and M = 64) decreasing when the number of beams / N-users, N is increased from 1 to 4 in accordance with one or more embodiments of the present disclosure.

[0048] FIG. 5 depicts exemplary AM- AM and AM-PM characteristics of the amplifier(s) 16a-16c with exemplary parameters and for a range of OBO values in accordance with one or more embodiments of the present disclosure.

[0049] FIG. 6 depicts exemplary amplifier(s) 16a- 16c transfer characteristics with exemplary parameters and for a range of OBO values in accordance with one or more embodiments of the present disclosure.

[0050] FIG. 7 depicts exemplary EVM for different values of M (number of array elements) and N (number of users or beams): (a) for an exemplary beamformer of an example conventional system, (b) for randomized OFDM signals at exemplary amplifier(s) 16a- 16c inputs of the example system in accordance with one or more embodiments of the present disclosure.

[0051] FIG. 8 depicts exemplary constellation clouds due to nonlinear compression at OBO of 3 dB (in the absence of AWGN) for M = 8, N = 2 versus M = 64and N = 8: (a) for an exemplary beamformer of an example conventional system, (b) for randomized OFDM signals at amplifier(s) 16a- 16c inputs in accordance with one or more embodiments of the present disclosure.

[0052] FIG. 9 depicts an exemplary Comparison of (a) EVM for an exemplary beamformer of an example system (in red), and (b) EVM for randomized OFDM Signals at exemplary amplifier(s) 16a- 16c inputs of the example conventional system (in blue) in accordance with one or more embodiments of the present disclosure.

[0053] FIG. 10 depicts exemplary SER in the AWGN Channel of an example system for Different Values of M (number of array elements) and N (number of users or beams) and for Different OBO: (a) for an exemplary beamformer of an example conventional system, (b) for randomized OFDM signals at exemplary amplifier(s) 16a- 16c inputs of the example system in accordance with one or more embodiments of the present disclosure.

[0054] FIG. 11 depicts exemplary Total Degradation of an example system for Different V alues of M (number of array elements) and N (number of users or beams): (a) for an exemplary beamformer of an example conventional system, (b) for randomized OFDM signals at exemplary amplifier(s) 16a- 16c inputs of the example system in accordance with one or more embodiments of the present disclosure.

[0055] FIG. 12 depicts exemplary ACLR of an example system for different values of M (number of array elements) and N (number of users or beams): (a) for an exemplary beamformer of an example conventional system, (b) for randomized OFDM signals at exemplary amplifier(s) 16a-16c inputs of the example system in accordance with one or more embodiments of the present disclosure.

[0056] FIG. 13 depicts exemplary distortion in the time domain OFDM signals of an example system in accordance with one or more embodiments of the present disclosure.

[0057] FIG. 14 depicts an exemplary SDR Evaluation of an example system in accordance with one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0058] Various detailed embodiments of the present disclosure, taken in conjunction with the accompanying FIGs., are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative. In addition, each of the examples given in connection with the various embodiments of the present disclosure is intended to be illustrative, and not restrictive.

[0059] FIGs. 1A through 14 illustrate systems and methods of applying randomization to signal inputs in transmission systems to improve decorrelation of the signals, such as in beamformer networks, orthogonal frequency division multiplexing, among other multi-signal aggregation and multiplexing schemes. The following embodiments provide technical solutions and technicalimprovements that overcome technical problems, drawbacks and / or deficiencies in the technical fields involving amplifiers in transmission and / or reception systems that become saturated when amplifying partially or otherwise ineffectively decorrelated signal. Through improved decorrelation of signals, linearity in the amplifier and / or management of peak- to- average power ratio (PAPR) can be improved for improved fidelity of the transmitted signal via improved dynamic range. As explained in more detail, below, technical solutions and technical improvements herein include aspects of improved decorrelation of signals input into an amplifier via randomization signals in the time-domain.

[0060] The fidelity of a multiplexed signal is affected as the multiplexed signal passes through an amplifier. For example, the fidelity of an Orthogonal Frequency Division Multiplexed (OFDM) signal is affected when it passes through, e.g., non-linear Power Amplifiers (PAs) within a beamforming network. In some embodiments, the beamforming network can mitigate the negative impact of amplifier(s) due to a decorrelating effect from the numerous signals in the multi-user system being beamformed and presented to each PA. The decorrelating effect can be enhanced via the introduction of a delay into signals input into the amplifier, thus mitigating high PAPR and improving dynamic range during large signal handling periods.

[0061] In some embodiments, techniques herein leverage per-element multi-user signal inputs, via randomization thereof, to improve performance according to one or more performance measures, such as, e.g., Error Vector Magnitude (EVM), Signal to Distortion Ratio (SDR), correlation coefficient, symbol error rates of the modulated symbols, Total Degradation (TD), and Adjacent Channel Power Ratio (ACPR), among others or any combination thereof. In some embodiments, techniques herein may provide improvements across different amplifier Output Back-Offs(OBOs), Signal-to-Distortion Ratio (SDR), Noise-to-Power Ratio (NPR), and Signal-to-Noise ratios (SNRs) including in the presence of additive white Gaussian noise (AWGN).

[0062] Techniques herein may use the decorrelation of signals to ensure that excursions to the peak of different sub-carriers at the input to the different power amplifiers are not synchronized in the time-domain, with the effect that the likelihood of the amplifiers being pushed into saturation, individually and / or simultaneously, is minimized. Since the beamformer output can be a weighted summation of the outputs of the power amplifiers, techniques herein can ensures that only a few of these power amplifiers on different antenna element paths are driven into saturation at a given time, the effect of high PAPR of the multicarrier signals is efficiently mitigated as a byproduct of beamforming.

[0063] Data can be obtained by a transmitter, including one or more pre-processing facilities such as an inverse fast Fourier Transform (IFFT), error reduction facility, normalization, among others or any combination thereof. The transmitter can multiplex the data into multiple informationbearing sub-carriers, such as data signals. The multiplexed information-bearing sub-carriers can parallelize the data stream, each parallel sub-carrier being provided to separate amplifier and antenna elements for directional transmission.

[0064] Inventors have appreciated that in such a beamforming transmitter, amplifier and antenna system (transmission system), multiple users can provide data for transmission which may cause multiple information-bearing sub-carriers to be input into each amplifier. However, the amplifier may have a limit on the number of information-bearing sub-carriers that the amplifier can process before the amplifier is saturated. Such saturation can lead to signal errors due to distortion. In some embodiments, the randomization can facilitate decorrelation of the information-bearing subcarriers input into an amplifier by assigning each information-bearing sub-carrier a particular timedelay, phase delay or both such that each information-bearing sub-carrier is separated in the time domain. As a result, even for large numbers of users, decorrelation can be ensured, reducing saturation, and therefore peaks in the amplifier. Accordingly, PAPR can be reduced, thus improving the performance of the amplifier and the overall transmission system.

[0065] In some embodiments, techniques to provide the randomization can include using a filter on beamformed sub-carrier signals prior to providing the signals to an amplifier. The filter can receive information-bearing sub-carriers being provided to a particular amplifier and introduce a delay on each information-bearing sub-carrier such that each information-bearing sub-carrier is assigned a different delay. As such, the filter can facilitate decorrelation of the information-bearing sub-carriers and improve the performance of the amplifier.

[0066] In some embodiments, a delay in the transmitted signal after amplification may be undesirable. Accordingly, techniques herein include providing a filter after the amplifier and before the antenna. The filter after the amplifier can be designed to remove the delay introduced by the filter before the amplifier. Accordingly, in some embodiments, the filter after the amplifier can include an inverse filter that is inverse to the filter before the amplifier. The inverse filter can assign each amplified information-bearing sub-carrier a particular time delay, phase delay or both that is inverse to the time delay, phase delay or both introduced by the filter prior to the amplifier such that the information-bearing sub-carriers are returned to their original relative positioning in the time domain.

[0067] In some embodiments, techniques to provide the randomization can include leveraging randomization that arises in Multiple-Input and Multiple-Output (MIMO) transmission systems. MIMO systems use a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation, and thus involve largenumbers of information-bearing sub-carriers due to servicing a large number of users. In some embodiments, a MIMO transmission system can introduce random phases to information-bearing sub-carriers. Typically, such random phases are a cause for concern for causing high instantaneous power levels in an amplifier when the random phases sometimes overlap. However, inventors have recognized that contrary to the typical concerns, random phases, when occurring for a sufficiently large number of sub-carriers, can enhance decorrelation similar to the use of a filter before the amplifier. Thus, the MIMO transmission system of embodiments herein can be designed to accommodate large numbers of sub-carriers and / or users to achieve greater the decorrelating effect from large numbers of sub-carriers input into the amplifier, for example by, e.g., optimizing thermal design and power levels of the signaling equipment to accommodate higher average power levels. In so doing, the amplifier can be adapted to leverage the random phases introduced by the MIMO techniques.

[0068] Based on such technical features, further technical benefits become available to users and operators of these systems and methods. Moreover, various practical applications of the disclosed technology are also described, which provide further practical benefits to users and operators that are also new and useful improvements in the art.

[0069] FIG. 1A depicts a block diagram of beamforming transmitting circuitry utilizing randomized delays in accordance with one or more embodiments of the present disclosure.

[0070] Techniques herein provide systems and methods to reduce PAPR (Peak to Average Power Ratio) in amplifier systems. The approach involves using filters to introduce random delays to multiplexing sub-carriers, which helps mitigate PAPR. The technique can be applied in both analog and digital filters. Embodiments can include randomizing delays by more than half a symbol to decorrelate sub-carriers and reduce PAPR.

[0071] In some embodiments, a beamformer network can include transmitters 12a, 12b through 12c. The transmitters 12a- 12c including hardware and / or software for pre-processing, processing and / or structure signals for transmission via antenna 18a, 18b through 18c. In some embodiments, the transmitters 12a-12c can include analog or digital circuitry, and / or software defined radios, or any combination thereof. While the term “transmitter” is used herein for simplicity of illustration, the term “transmitter” may refer to a transmitter or to a transceiver or both, or any other hardware and / or software configured to transmit a signal.

[0072] In some embodiments, the beamformer network may be formed of any of one or more devices that incorporate the transmitters 12a-12c, delay facilities 14a, 14c through 14c, amplifiers 16a- 16c and antennas 18a- 18c. Examples of such devices can include, without limitation, a satellite payload of a satellite, WiFi radio, Bluetooth radio, cellular network transmitter, access point, or basestation, a satellite or satellite constellation ground station, or any other stationary, mobile, portable or other transmission system or any combination thereof, including those included in, e.g., laptop computers, mobile computing devices, wearable devices, internet or intranet networking equipment, RADAR transmitters, or any other wireless communication equipment or any combination thereof.

[0073] In some embodiments, the transmitters 12a-12c may include componentry and / or software for creating the carriers and / or sub-carriers of input data, such as an oscillator, modulator, an inverse fast Fourier transform (IFFT) followed by an optional cyclic prefix (CP) insertion block, among other hardware and / or software component to create the carrier(s) and / or sub-carrier(s).

[0074] In some embodiments, the transmitters 12a-12c may include an electronic oscillator to generate a radio frequency signal. The electronic oscillator may generate a sinusoidal wave of constant amplitude, called the carrier wave. In some embodiments, the electronic oscillator maybe a crystal oscillator in which the frequency is precisely controlled by the vibrations of a quartz crystal, or may be a software-define component, or any other digital and / or analog componentry (e.g., a numerical controlled oscillator) or any combination thereof.

[0075] In some embodiments, the carrier wave may be modified by a modulator circuit to add the information to be transmitted to the carrier wave. To do so, the modulator may vary some aspect of the carrier wave to represent the information being carried. The information is provided to the transmitter as an electronic signal called the modulation signal. The modulation signal may be an audio signal, which represents sound, a video signal which represents moving images, or for data in the form of a binary digital signal which represents a sequence of bits, a bitstream. Different types of transmitters use different modulation methods to transmit information. For example, the modulator may be configured to implement AM (amplitude modulation) by modulating the amplitude (strength) of the carrier wave in proportion to the modulation signal. In another example, the modulator may implement FM (frequency modulation) by modulating the frequency of the carrier in proportion to the modulation signal. In another example, the modulator may implement FSK (frequency-shift keying) to transmit digital data by modulating the frequency of the carrier is between two frequencies which represent the two binary digits, 0 and 1. In another example, the modulator may implement FDM (frequency-division multiplexing), including OFDM (orthogonal frequency-division multiplexing), which is a family of digital modulation methods that may be used in high bandwidth systems such as Wi-Fi networks, cellphones, digital television broadcasting, and digital audio broadcasting (DAB) to transmit digital data using a minimum of radio spectrum bandwidth. For example, single carrier (SC) OFDM may be used in long-term evolution (LTE) and / or 5GNR cellular networks for the return link. To implement OFDM, the modulator may use multiple radio carrier waves (sub-carriers) closely spaced in frequency, whichare transmitted within the radio channel, with each carrier modulated with bits from the incoming bitstream so multiple bits are being sent simultaneously, in parallel. At the receiver the carriers are demodulated and the bits are combined in the proper order into one bitstream such as, without limitation, using an inverse fast Fourier transform at the transmitter and a fast Fourier transform at the receiver.

[0076] Herein, the terms “carrier” and “sub-carrier” refer to a periodic waveform (e.g., sinusoidal) that initially carries no information, and, through modulation, one or more of the waveform’s properties are modified by an information bearing signal (called the message signal or modulation signal) to become an information-bearing carrier or sub-carrier. The carrier may either to transmit the information through space as an electromagnetic wave (as in radio communication), or to allow several carriers at different frequencies to share a common physical transmission medium by frequency division multiplexing (as in a cable television system).

[0077] In some embodiments, to enable directional signal transmission and spatial selectivity, the carrier wave, during modulation, may be split into multiple information-bearing sub-carriers, and the transmitters 12a- 12c may be configured to beamform the information-bearing sub-carriers. Thus, the transmitters 12a- 12c may include one or more beamformers that include hardware and / or software components to control the phase and relative amplitude of each information-bearing subcarrier of a given input data.

[0078] In some embodiments, the beamformer(s) of the transmitters 12a- 12c may include delay -and-sum (e.g., fixed or switched beam) beamformers, and / or adaptive beamformers (e.g., phased array). An adaptive beamformer may include desired signal maximization mode and / or interference signal minimization or cancellation mode.

[0079] In some embodiments, delay-and-sum beamformers, such as the Butler matrix, can use a fixed set of weightings and time-delays (or phasings) to combine the signals from the sensors in the array, primarily using only information about the location of the sensors in space and the wave directions of interest. In contrast, adaptive beamforming techniques (e.g., which may use MUSIC or SAMV algorithms to facilitate the determination of the beamforming weights) may combine this information with properties of the signals actually received by the array, such as to improve rejection of unwanted signals from other directions. This process may be carried out in either the time or the frequency domain. An adaptive beamformer may automatically adapt its response to different situations. In some embodiments, a criterion may be set up to allow the adaptation to proceed such as minimizing the total noise output as such an example.

[0080] In some embodiments, the information-bearing sub-carrier(s) may be provided to an amplifier 16a, 16b through 16c. The amplifiers 16a- 16c may include hardware and / or software componentry to increase the magnitude of a signal (a time-varying voltage or current). The amplifiers 16a- 16c may be two-port electronic circuits that use electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of the information-bearing subcarriers) applied to its input terminals, producing a proportionally greater amplitude signal at its output.

[0081] That output, the amplified information-bearing sub-carriers, may be provided to the antennas 18a- 18c. Due to the beamforming by the transmitters 12a- 12c, the antennas 18a- 18c may emit beamformed signal(s) la, lb through 1c. For beamforming, the transmitters 12a-12c may modulate the carrier wave for a given input data, e.g., from a particular user, via OFDM to create multiple information-bearing sub-carriers for that input data. Each information-bearing sub-carrier may be provided to a separate amplifier 16a-16c and emitted by separate antennas 18a-18c. Basedon the phase delays, the constructive and destructive interference of the emitted signals may form a particular one of the beamformed signals la-lc that propagates in a particular direction toward a desired target (e.g., a desired receiver).

[0082] In some embodiments, the number of uses and / or the number of information-bearing subcarriers being processed by each amplifier 16a- 16c can continuously, intermittently, periodically, or irregularly increase to greater than a total power range of the amplifiers 16a- 16c, such as the PAPR exceeding an upper limit of which the amplifiers 16a- 16c are capable. In such scenarios, the information-bearing sub-carrier(s) can experience degradation and loss such that the fidelity of the signal is decreased. However, in some embodiments, these high power scenarios can be mitigated by imposing a randomized delay to each information-bearing sub-carrier such that the information-bearing sub-carriers being processed by a particular amplifier 16a- 16c is distributed temporally, thus reducing the peaks in the signals being processed by the amplifiers 16a- 16c.

[0083] In some embodiments, the beamformer network can include a delay facilities 14a, 14b through 14c associated with the amplifiers 16a- 16c. For example, each amplifier 16a- 16c may be preceded by a respective delay facility 14a-14c.

[0084] In some embodiments, the delay facilities 14a- 14c may receive information-bearing subcarriers from one or more of the transmitters 12a- 12c and impose a different, randomized, delay on each of the received information-bearing sub-carriers. In some embodiments, the delay may be randomized in that arbitrary delay lengths may be pre-mapped to particular characteristics or combinations of characteristics of the information-bearing sub-carriers. Such characteristics can include, without limitation, frequency, phase, amplitude, data size (e.g., how much data or information the respective information-bearing sub-carrier is carrying), among other characteristics or any combination thereof. Thus, upon receiving an information-bearing sub-carrier, the delay facility 14a- 14c may determine the characteristic(s) for that information-bearing sub-carrier and apply the delay length mapped to that characteristic(s).

[0085] In some embodiments, the delay for a given characteristic(s) may be configured via randomization at the time of receiving the information-bearing sub-carrier. Thus, an arbitrary delay length may be mapped in real-time to particular characteristics or combinations of characteristics of the information-bearing sub-carrier at the time of receiving the information-bearing sub-carrier. Thus, upon receiving an information-bearing sub-carrier, the delay facility 14a- 14c may determine the characteristic(s) for that information-bearing sub-carrier, determine a random delay length, and apply the delay length to that characteristic(s).

[0086] In some embodiments, the delay facilities 14a- 14c may be signal filters. The filter(s) may change the phase relationship among various frequencies. Thus, the filter(s) may be any suitable hardware and / or software for applying such changes in the phase relationships. In so doing, the filter(s) may introduce a different delay at each frequency, e.g., as the information-bearing subcarrier reaches input-to-output quadrature, e.g., at co=l / RC (i.e., phase shift is 90°). Thus, the filter(s) may be designed such that at certain frequencies and / or phases, an information-bearing sub-carrier is delayed by an associated amount. As detailed above, such amount of delay may be a random or arbitrary value, meaning that the delay does not otherwise carry any relationship to the signal being delayed.

[0087] In some embodiments, the delay may be limited to a specified range. For example, a delay below a lower threshold may not provide sufficient decorrelation to mitigate PAPR, while a delay above an upper threshold may add latency without a practical improvement to PAPR and / or other performance metrics. In some embodiments, the lower threshold may be a half symbol length or more, and the upper threshold may be, e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, or moresymbols length, or may be, e.g., 5, 10, 15, 20, 25, 30, 45, 60 or more seconds in length, or other suitable upper and lower thresholds.

[0088] In some embodiments, the filter(s) may be signal processing linear filter(s), such as an all-pass, low-pass, high-pass, band-pass, band-stop, notch, comb or other linear filter or any combination thereof. In some embodiments, the filter(s) may be signal processing non-linear, timevariant, time-invariant, causal infinite impulse response, finite impulse response or other filter type or any combination thereof. In some embodiments, the filter(s) may be analog, digital, quartz, piezoelectric, Surface Acoustic Wave (SAW), Bulk Acoustic Wave (BAW), Garnet, atomic or other filter or any combination thereof.

[0089] In some embodiments, the random or organized, quasi random time delays may be realized through the filter where the filter has a frequency phase response. Thus, where there are multiple information-bearing sub-carriers passing through an amplifier 16a- 16c, where each informationbearing sub-carriers is at a different frequency, then the phase response of the filter is chosen such that the output of the information-bearing sub-carriers at the output of the filter will have a particular time delay associated with it. The filter(s) may be provided at the input to the amplifier(s) 16a- 16c and then have the inverse of the filter or the output to undo the phase.

[0090] In some embodiments, the delay facilit(ies) 14A-14c may be or include one or more other delay inducing mechanisms, such as a neural network. A neural network can be designed to model an analog circuit at the input and / or output of the amplifier 16a- 16c, and thus impose the randomized delay into the amplifiers 16a- 16c. In some embodiments, the neural network may be trained to ingest a signal and output the signal augmented with a randomized delay. For example, the neural network will use features such as frequency, amplitude or other characteristics of the signal or any combination thereof to determine a delay magnitude. The output of the neuralnetwork may be the delay, which may then be added to the signal, or the output may be the delayed signal.

[0091] For example, when there is one amplifier, and that amplifier may normally have several signals going into it. Then prior to the amplifier, the delay facility 14a- 14c may be provided with a phase response, and each of those signals would be provided as input to the delay facility 14a-14c, and the signals go through the delay facility 14a- 14c, and one signal come out, and then they are applied to the amplifier.

[0092] Accordingly, embodiments herein may impart random delay variations to signals on different frequencies. Thus, for multiple information-bearing sub-carriers which are co-located, e.g., are nearby in the frequency, the information-bearing sub-carriers experience the same rate of change of phase, but that rate of change of phase is going to be different compared to the rate of change of phase that some other set of sub carriers which are further away in frequency would experience, and the rate of change of phase is effectively the delay that that sub carrier experiences. Therefore, the delays that are experienced by different sub carriers going into the amplifiers 16a-16c can be randomized, and then at the output of the PA, we will have an all pass filter with exactly the opposite arrangement of poles and zeros, so that that random delay variation that we are artificially introducing, just so that this peak to average variations across different sub-carriers are not synchronized. Thus, there may be a filter at the output of the PA to undo the effect that has been introduced, and the overall effect is to minimize the peak to average variation of the amplified signal.

[0093] In some embodiments, the delays may be selected to ensure sufficient separation to achieve the peak-to-average variations across the different information-bearing sub-carriers prevents saturation of the respective amplifier 16a- 16c. Such delays may include an offset of one sub carrierwith respect to the other being greater than or equal to half a symbol. Then, because the individual symbols that are being transported on each sub carriers are random, one the sub-carriers are offset by half a symbol (plus or minus half a symbol), the sub-carriers become sufficiently orthogonal to each other to be separate in the time domain, and thus become uncorrelated.

[0094] In some embodiments, the half symbol offset may be used because the symbol streams are in the time domain, then the correlation with other symbol streams is minimized, e.g., expected value of the multiplication and then summation between the symbol streams is minimized. Thus, once delay is added to one waveform with respect to the other waveform by half a symbol or more, then the waveforms become more decorrelated than without the delay.

[0095] FIG. IB- II depict plots of three exemplary information-bearing sub-carriers before and after delay by the delay facilities 14a- 14c in accordance with one or more embodiment of the present disclosure.

[0096] In some embodiments, the plots show OFDM sub-carriers at three different frequencies, as in the time domain plot depicted in FIGs. IB- 11 and in the spectral diagrams. The plots may show sub-carriers at the three frequencies, 0.1, 0.2 and 0.4. Because these sub-carriers are real valued, the images additionally appear as the negative frequencies.

[0097] FIG. IB illustrates a spectral waveform of three signals in accordance with one or more embodiments of the present disclosure. In some embodiments, considering an input x(n) which is comprised of three sinusoidal pulses of different frequencies, these are three truncated sinusoids; each of length 60 samples may be multiplied by a tapering function in time domain (such as a time domain Hamming windowing).

[0098] FIG. 1C illustrates impulses of the frequency domain of the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure. The plot depicts the functionX(f): DTFT of x(n). Thus, the plot represents a frequency domain representation of the input x(n), which shows six “impulses” because the input x(n) is real-valued (i.e., for each frequency, there is a mirror image present)

[0099] FIG. ID depicts a pole-zero diagram for the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure. The plot depicts input x(n) of FIG. IB that is passed through an Beamformer network with the illustrated Pole -Zero diagram.

[0100] FIG. IE depicts a magnitude response for the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure. The plot depicts the location of tones in the input x(n) using the vertically oriented arrows positioned along the x-axis.

[0101] FIG. IF depicts phase response the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure.

[0102] FIG. 1G depicts phase response (unwrapped) for the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure. The plot depicts the location of tones in the input x(n) using the vertically oriented arrows positioned along the x-axis.

[0103] FIG. 1H illustrates group delay of the three signals of FIG. IB in accordance with one or more embodiments of the present disclosure. The plot depicts the location of tones in the input x(n) using the vertically oriented arrows positioned along the x-axis.

[0104] FIG. II depicts an output y(n) from the group delay of three signals of FIG. IB in accordance with one or more embodiments of the present disclosure. In some embodiments, as depicted, frequency / =0.4 is no longer present. Moreover, since the group delay of the beamformer network at / =().1 is greater than that at f-Q.2, the position of the pulses is switched at the output of the filter.

[0105] As illustrated by FIGs. 1B-1I, the locations of poles and zeros in the z plane are shown. For this example, the poles and zeros are very close to each other. Thus, in terms of magnitude, the poles and zeros almost cancel each other out (FIG. ID). As a result, the poles and zeros do not present a substantial magnitude variation. However, when the frequency response is evaluated, the frequency rises rapidly (FIG. IE). Thus, the phase response similarly changes rapidly, because it will go from zero to pole to zero to pole.

[0106] Indeed, at the locations of each grouping of poles and zeros, the phase changes rapidly compared to everywhere else (FIG. IF), while at other places, the variation of the phase is not as significant as at the location of the groupings of poles and zeros. The groupings of poles and zeros are located at the frequency of one of the sinusoids that point one hertz. The changes in phases is greater at the frequency of 0.1, and that is because the phase is going from minus pi to plus pi.

[0107] Upon unwrapping the phase (FIG. 1G), the rate of change of phase at the location of this sub-carrier at the frequency of 0.1 is greater than the rate of change of the phase at the location of the sub-carrier at the frequency of 0.2. Where the derivative of this phase response is taken as a function of frequency, the group may be delayed (FIG. 1H). Indeed, in this example, the subcarrier at the frequency of 0.1 was delayed by 150 samples, and the sub-carrier at the frequency of 0.2 received a smaller delay of 10 samples. Accordingly, variability can be introduced into the delay that the sub-carriers experience. Where less delay variation or more delay variation across different sub carriers is desired, the locations of the poles and zeros (as illustrated in FIG. ID) can be varied to customize the delays of the sub-carriers based on phase and / or frequency.

[0108] In some embodiments, the delay facilities 14a- 14c may include respective beamformers themselves. Indeed, in a massive MIMO type of arrangement, the multiple beams, which are formed by multiple antennas 18a- 18c, may provide sufficient randomization in the time domainfor decorrelation. Indeed, the beamformer network could include a complicated beamformer which implements multiple beams using multiple antenna elements and provides randomization.

[0109] Accordingly, in some embodiments, the control of the beamformer network can be optimized to increase randomization via the massive MIMO implementation. Such optimization may include controlling the transmitters 12a- 12c to push the amplifiers 16a- 16c further into saturation without exceeding an upper threshold, which, counter to the typical system, can be leveraged to mitigate the PAPR in the amplifiers 16a- 16c.

[0110] In typical transmission systems, greater saturation of the amplifier(s) is understood to increase the likelihood of distortion that can cause errors and degradation in the informationbearing sub-carriers. Accordingly, typical systems avoid saturating amplifiers.

[0111] In some embodiments, on the other hand, when there are randomized arrangement of different multiplexed signals, such as OFDM signals, going into the amplifiers 16a-16c and there are multiple amplifiers 16a- 16c, and all of these amplifiers 16a- 16c are subjected to this type of randomized, super imposed multiplexed signal, the complementary multiplexed signals exhibit a PAPR similar to that expected of a conventional single carrier signal. Thus, the beamformer itself can provide randomized multiplexed sub-carriers when provided with a sufficient number of subcarriers. In some embodiments, in general, more multiplexed signals through the amplifier will achieve a greater randomization, and thus decorrelation, effect of the signals to reduce PAPR. The number of multiplexed signals, though, may be limited by the design constraints of the transmitters 12a- 12c and / or amplifiers 16a- 16c. Thus, the performance of the system may be achieve through balancing the number of multiplexed signals with the capabilities of the hardware.

[0112] Indeed, in some embodiments, the amplifiers 16a-16c, transmitters 12a-12c, antennas 18a-18c or any other components or any combination thereof may be designed to accommodate highersignal density, and communications may be routed such that a given transmitter 12a is tasked with a threshold level of signal density, e.g., via assignment to a threshold number of users. As a result, the beamformer network can be customized to higher signal density across each transmitter such that randomness is increased and PAPR is improved for each amplifier 16a- 16c.

[0113] FIG. 2 depicts another block diagram of beamforming transmitting circuitry utilizing randomized delays in accordance with one or more embodiments of the present disclosure.

[0114] Techniques herein provide systems and methods to reduce PAPR in amplifier systems. The approach involves using filters to introduce random delays to multiplexing sub-carriers, which helps mitigate PAPR, and then removing the random delays after amplification. The technique can be applied in both analog and digital filters. Embodiments can include randomizing delays by at least half a symbol to decorrelate carriers and reduce PAPR.

[0115] In some embodiments, a beamformer network can include one or more transmitters 22a. The transmitters 22a-22c including hardware and / or software for pre-processing, processing and / or structure signals for transmission via antenna 28a, 28b through 28c. In some embodiments, the transmitters 22a-22c can include analog or digital circuitry, and / or software defined radios, or any combination thereof. While the term “transmitter” is used herein for simplicity of illustration, the term “transmitter” may refer to a transmitter or to a transceiver or both, or any other hardware and / or software configured to transmit a signal.

[0116] In some embodiments, the beamformer network may be formed of any of one or more devices that incorporate the transmitters 22a-22c, delay facilities 24a, 24c through 24c, amplifiers 26a-26c and antennas 28a-28c such as any hardware and / or software as detailed above in FIG. 1A.

[0117] In some embodiments, the beamformer network can include a delay facilities 24a, 24b through 24c associated with the amplifiers 26a-26c. For example, each amplifier 26a-26c may be preceded by a respective delay facility 24a-24c.

[0118] In some embodiments, the delay facilities 24a-24c may be receive information-bearing sub-carriers from one or more of the transmitters 22a and impose a different, randomized, delay on each of the received information-bearing sub-carriers. In some embodiments, the delay may be randomized in that arbitrary delay lengths may be pre-mapped to particular characteristics or combinations of characteristics of the information-bearing sub-carriers. Such characteristics can include, without limitation, frequency, phase, amplitude, data size (e.g., how much data or information the respective information-bearing sub-carrier is carrying), among other characteristics or any combination thereof. Thus, upon receiving an information-bearing subcarrier, the delay facility 24a- 24c may determine the characteristic(s) for that information-bearing sub-carrier and apply the delay length mapped to that characteristic(s).

[0119] In some embodiments, the randomization may be randomized in that at the time of receiving the information-bearing sub-carrier. Thus, an arbitrary delay length may be pre-mapped to particular characteristics or combinations of characteristics of the information-bearing subcarrier at the time of receiving the information-bearing sub-carrier. Thus, upon receiving an information-bearing sub-carrier, the delay facility 24a-24c may determine the characteristic(s) for that information-bearing sub-carrier, determine a random delay length, and apply the delay length to that characteristic(s).

[0120] In some embodiments, the delay facilities 24a-24c may be signal filters. The filter(s) may changes the phase relationship among various frequencies. Thus, the filter(s) may be any suitable hardware and / or software for applying such changes in the phase relationships. In so doing, thefilter(s) may introduces a different delay at each frequency, e.g., as the information-bearing subcarrier reaches input-to-output quadrature, e.g., at co=l / RC (i.e., phase shift is 90°). Thus, the filter(s) may be designed such that at certain frequencies and / or phases, an information-bearing sub-carrier is delayed by an associated amount. As detailed above, such amount of delay may be a random or arbitrary value, meaning that the delay does not otherwise carry any relationship to the signal being delay.

[0121] In some embodiments, the filter(s) may be signal processing linear filter, such as an all-pass, low-pass, high-pass, band-pass, band-stop, notch, comb or other linear filter or any combination thereof. In some embodiments, the filter(s) may be signal processing non-linear, timevariant, time-invariant, causal infinite impulse response, finite impulse response or other filter type or any combination thereof. In some embodiments, the filter(s) may be analog, digital, quartz, piezoelectric, surface acoustic wave (SAW), bulk acoustic wave (BAW), Garnet, atomic or other filter or any combination thereof.

[0122] In some embodiments, the random or organized, quasi random time delays may be realized through the filter where the filter has a frequency phase response. Thus, where there are multiple information-bearing sub-carriers passing through an amplifier 26a-26c, where each informationbearing sub-carriers is at different frequency, then the phase response of the filter is chosen such that the output of the information-bearing sub-carriers at the output of the filter will have a particular time delay associated with it. The filter(s) may be provided at the input to the amplifier(s) 26a-26c and then have the inverse delay facilities 27a, 27b through 27c that are inverse to the delay facilities 24a-24c to undo the delay after amplification.

[0123] For example, when there is one amplifier, and that amplifier may normally have several signals going into it. Then prior to the amplifier, the delay facility 24a- 24c may be provided witha phase response, and each of those signals would be provided as input to the delay facility 24a-24c, and the signals go through the delay facility 24a-24c, and one signal come out, and then they are applied to the amplifier.

[0124] Thus, for multiple information-bearing sub-carriers which are co-located, e.g., are nearby in the frequency, the information-bearing sub-carriers experience the same rate of change of phase, but that rate of change of phase is going to be different compared to the rate of change of phase that some other set of sub carriers which are little far away would experience, and the rate of change of phase is effectively the delay that that sub carrier experiences. Therefore, the delays that are experienced by different sub carriers going into the amplifiers 26a-26c can be randomized, and then at the output of the amplifiers 26a-26c, there may be the inverse delay facilities 27a-27c that have an opposite arrangement of poles and zeros compared to the poles and zeros of the delay facilities 24a-24c, so that that random delay variation that we are artificially introducing, just so that this peak to average variations across different sub-carriers are not synchronized. Therefore, the delay variation is artificial. The delay variations are undesirable for transmission, and so the inverse delay facilities 27a-27c undo the effect introduced by the delay facilities 24a-24c, to minimize the peak to average variation without affecting the timing or orientation of the beamformed signal 2a.

[0125] In some embodiments, the delays may be selected to ensure sufficient separation to achieve the peak-to-average variations across the different information-bearing sub-carriers prevents saturation of the respective amplifier 26a-26c. Such delays may include an offset of one sub carrier with respect to the other being greater than or equal to half a symbol. Then, because the individual symbols that are being transported on each sub carriers are random, one the sub-carriers are offsetby half a symbol (plus or minus half a symbol), the sub-carriers become sufficiently orthogonal to each other to be separate in the time domain, and thus become uncorrelated.

[0126] In some embodiments, the half symbol offset may be used because in QPSK or qualms, symbol stream, which is in the time domain, then do the correlation of the waveform with the shifted waveform, then the average value of that correlation goes to zero, e.g., expected value of the multiplication and then summation. Thus, once delay is added to one waveform with respect to the other waveform by half a symbol or more, then the waveforms become uncorrelated.

[0127] As a result, in some embodiments, the delayed information-bearing sub-carriers may be input into the amplifiers 26a-26c for amplification of the delayed information-bearing sub-carriers prior to transmission. In so doing, saturation of the amplifiers 26a-26c may be mitigated and errors in the beamformed signals 2a may be reduced.

[0128] FIG. 3 depicts another block diagram of beamforming transmitting circuitry utilizing randomized delays in accordance with one or more embodiments of the present disclosure.

[0129] Techniques herein provide systems and methods to reduce PAPR in PA (Power Amplifier) systems. The approach involves using all-pass filters to introduce random delays to OFDM (Orthogonal Frequency Division Multiplexing) sub-carriers, which helps mitigate PAPR. The technique can be applied in both analog and digital filters. Embodiments can include randomizing delays by more than half a symbol to decorrelate sub-carriers and reduce PAPR.

[0130] FIG. 3 shows a system architecture including N OFDM transmitters 42 using quadrature amplitude modulation (QAM), out of which one is for the desired user (N is the number of users or beams, with one user per beam). Each of these N OFDM transmitters 42 can include an OFDM modulator 51, such as a 16-QAM modulator 51, and an inverse fast Fourier transform (IFFT) 52 followed by an optional cyclic prefix (CP) insertion block. The IFFT 52 length at each OFDMtransmitter 42 is Ns X N, e.g., there are Ns X N sub-carriers, where Nsis the number of sub-carriers per user. The input to the IFFT 52 for the nthuser

[0131] (0 < n < N) comprises Ns QAM symbols in the frequency domain, which are mapped by the IFFT 52 to the sub-carriers indexed from [nNs + 1, nNs + 2,+ l)Ns]. The rest of the sub-carriers (from 1 to Ns X N) are zeroed-out. This results in an orthogonal multiple access scheme for N users, e.g., where the OFDM signals for different users are separated in frequency (e.g., their OFDM sub-carriers do not overlap, and there is no co-channel interference in the absence of nonlinearity). The desired user can be placed at the center of the band, e.g., its index, that denoted as nd, is set to | j. This ensures that the adjacent channel interference for the desired user is symmetrical from both the sides of its spectral occupancy.

[0132] The transmitted OFDM signal for a given user can be sent to a user-specific beamformer 53. The beamformer 53 for each user splits the incoming OFDM signal into M branches, where M is the number of elements of the transmit antenna array. A user beam-specific phase offset can be applied to each of these M elemental branches. The beamforming network can be, thus, implemented using a matrix W of beamforming weights, where the matrix size is M X N and the nthcolumn vector of this matrix has M beamforming weights of the nthuser. All M X N elements of this beamforming matrix W are complex phasors expressible as exp(j2n6m,n), e.g., the amplitude of a beamforming coefficient is unity (the beamformer 53 does not use any amplitude taper). The N columns of the beamforming weight matrix are orthogonal (consequently, even if multiple users are to share the same sub-carrier, the OFDM signals transmitted to these users would not interfere among themselves).

[0133] Each of the M array elements has an associated power amplifier. The input to the mthamplifier(s) 16a-16c (1 < m < M) is the superposition of all N signals generated by the userspecific beamformer 53s on the mtharray element.

[0134] As noted above, the IFFT 52 output for the nthuser can be expressed as Xn = Fsn, where F is the IFFT 52 matrix. In this case, Xncan be sent to the beamformer 53 for the nthuser, e.g., the nthcolumn of the matrix W, which generates M replicas of Xn given as follows:[WZl.nXn, W .nXn, ... Wm.nXn, ... , WM.nXn

[0135] In some embodiments, the contribution of the nth user to two different elements (e.g., power amplifier 46) m and m, e.g., the two columns Wm.nxn and Wm.nxn of the above matrix. These two columns differ only in the nth beamformer 53 complex phasor terms, e.g., Wm nand ^m.nsuch that the correlation coefficient between these two column vectors is unity.

[0136] For example, suppose the two phasors Wm,n and Wm.n are unity. In this case, the correlation coefficient between Wm,nxn and Wm.nxn is also unity since the two columns become identical. When these phasors have nonzero phases, the magnitude of the correlation coefficient still remains unity since the presence of nonzero phase has no effect on the magnitude.

[0137] In some embodiments, the aggregate inputs to these two elements (e.g., the corresponding nonlinear power amplifier 46) can be dissimilar but can still exhibit a high correlation. Indeed, the associated signals can be written as two different linear superpositions of the same N underlying OFDM user signals, specifically, sm =Wm,nxn for the mth element and sm = ^NWrn,nxn for the mth element.

[0138] In some embodiments, even under an assumption that a user’s OFDM signal is orthogonal to all the rest of the users’ signals (e.g., the inner product xHx - 1 if n = n and it is zero otherwise), the correlation between the signals sm and sm can take a substantial nonzero value since the underlying OFDM signals are equivalent.

[0139] Accordingly, in some embodiments, the inner product may be=The phases 9™’m, which are the differences of the phases of 1 ^>nand W^ncan be taken as randomly distributed over [0,2?r]. Therefore, when the number of users N is sufficiently large, the in-phase and the quadrature components of- by the virtue of the central limit theorem - can become zero mean Gaussian distributed random variables. In this case, the magnitudefollows Rayleigh distribution whose mean, e.g., the average of the magnitude of the correlation, is not zero. Indeed, the Rayleigh distributed random variable can take substantial excursions away from zero.

[0140] Accordingly, the result in FIG. 4 illustrates that the impairment due to the nonlinearity remains significantly correlated even for large values of N and M for the conventional beamformer 53 such that the correlation coefficients (over all M elements, for M = 8 and M = 64) decreases when the number of beams / N-users, N is increased from 1 to 4. However, further increase in N may be less effective to reduce the coefficient of correlation.

[0141] To circumvent this problem, the filter 44 may randomize OFDM signals prior to input into the power amplifier 46. In this model, the signals on the two elements can be written as sm=the mth element.

[0142] Therefore, in some embodiments, each user’s beamformer 53 may provide different OFDM signals on the M different power amplifier 46 inputs, except for the desired user nd, which, forthe purpose of beamforming, is taken to send the identical OFDM signal xnd on all M elements. In some embodiments, using the above, the beamformer 53 for different users can impart different delay shifts to the input OFDM signals. The delays may be reversed at the output of the power amplifier 46 via a filter 47 that is inverse to the filter 44. At the receiver of this desired user, the beamforming functionality is obtained since individual elements’ outputs are coherently combined.

[0143] Under the assumption that=0 unless n = n and m = m, the contribution of the undesired users’ signals on the two elements in and m, e.g.,become orthogonal.EXAMPLE - SIMULATED TRANSMISSION SYSTEM UTILIZING RANDOMIZED PERELEMENT MULTI-USER SIGNAL INPUT TO POWER AMPLIFIERS

[0144] As noted above, the IFFT output for an nthuser can be written as Xn = Fsn, where F is the IFFT matrix. For the sake of simplicity, let us ignore the insertion of the CP and the parallel-to-serial conversion at the OFDM transmitter. In this case, can be written that Xn is sent to the beamformer for the nthuser, e.g., the nthcolumn of the matrix W, which generates M replicas of Xn given as follows:[VFl.nXn, VF2,nXn, ... Wm.nXn, ... , VFw.nXn]

[0145] Consider the contribution of the nthuser to two different elements (PAs) m and in, e.g., the two columns Wm,nXn and Wm,nXn of the above matrix. These two columns differ only in the nthbeamformer’s complex phasor terms, e.g., W‘nnandand it is easy to see that the correlation coefficient between these two column vectors is unity.

[0146] For example, suppose the two phasors Wm,n and Wm~n are unity. In this case, clearly the correlation coefficient between Wm,nxnand Wm~nxnis also unity since the two columns become identical. When these phasors have nonzero phases, the magnitude of the correlation coefficient still remains unity since the presence of nonzero phase has no effect on the magnitude.

[0147] The actual situation is not so dire; the aggregate inputs to these two elements (e.g., the corresponding nonlinear PAs) are certainly dissimilar but they can still exhibit a high correlation. To show this, we write these signals as two different linear superpositions of the same N underlying OFDM user signals, specifically, Sm =Wm,nXn for the mthelement and s™. =Wm,nXn for the mthelement.

[0148] In some embodiments, even under an assumption that a user’s OFDM signal is orthogonal to all the rest of the users’ signals (e.g., the inner product xHx- = 1 if n = n and it is zero otherwise), the correlation between the signals Sm and Sm can take a substantial nonzero value since the underlying OFDM signals are identical.

[0149] Under the assumption mentioned here, it can be shown that the inner products^s^ =The phases 0,™’’", which are the differences of the phases of l / V^ ^and IKm.ncanbe taken as uniformly randomly distributed over [0,2TT] . Therefore, when the number of users N is sufficiently large, the in-phase and the quadrature components of- by the virtue of the central limit theorem - become zero mean Gaussian distributed random variables. In this case, the magnitude follows Rayleigh distribution where the mean - e.g., the average of the magnitude of the correlation - is not zero. In fact, the Rayleigh distributed random variable can take substantial excursions away from zero.

[0150] Accordingly, a simulation-based evaluation of the (normalized) correlation coefficient ( ) is performed. The result in FIG. 4 shows that the impairment due to the nonlinearity remains significantly correlated even for large values of N and M for the conventional beamformer suchthat the correlation coefficients (over all M elements, for M = 8 and M = 64) decreases when the number of beams / N -users, N is increased from 1 to 4. However, further increase in N does not noticeably reduce the coefficient of correlation.

[0151] To circumvent this problem, we have simulated a hypothetical model of completely randomized OFDM signals. In this model, the signals on the two elements are written as sm=the mthelement.

[0152] Essentially, each user’s beamformer is taken to send completely different OFDM signals on the M different PA inputs, except for the desired user nd, which, for the purpose of beamforming, is taken to send the identical OFDM signal xnd on all M elements. An alternate, more realistic, scenario which can be modelled in this manner is when the beamformers for different users impart different delays shifts to the input OFDM signals (instead of the phase shifts). At the receiver of this desired user, the beamforming functionality is obtained since individual elements’ outputs are coherently combined.

[0153] Under the assumption that=0 unless n = n and m = in, it is easy to see that the contribution of the undesired users’ signals on the two elements in and m, e.g., Sn=i,n*ndxm,n and Sn=i,n*ndxm,n become orthogonal.

[0154] A simulation is conducted to evaluate the efficacy of beamforming in mitigating the amplifier-induced nonlinear distortion. The number of sub-carriers per user, NS, is typically set to 128. The number N of users and the number M of elements are typically varied over the following pairs: [N = 1, M = 1], [N = 2, M = 8], [A = 4, M = 16], [A = 8, M = 64], and [A = 32, M = 256]. The OFDM cyclic prefix is either configured to be 5% of the total number ASA of sub-carriers, or it is set to zero. Indeed, the CP does not play a role in determining the performance since themodelled nonlinearity is memoryless, and the channel is assumed to not introduce any other delay dispersion effect.

[0155] For modelling the nonlinear power amplifier, the well-known Saleh’s model is adopted as detailed above. The model parameter values used are O.AM = 1, / 3 AM = 0.25, aPM = 4, [3PM = 2.1. The corresponding AM to AM and AM to PM transfer characteristics are shown in FIG. 6.

[0156] Let yb= yb+ jybbe the bthcomplex- valued symbol or constellation point (j = — 1) of the simulated B = 16-QAM modulation (the index b E [1,2, ... ,16]).

[0157] For the sake of simplicity, assume that a total L X B symbols are received and they are segregated into B clusters each having L symbols. Let yb= yb i+ jyb lbe the Ithreceived QAM symbol that is mapped to the bthcluster. The centroid of each cluster is calculated as the average value of all the received symbols mapped to that cluster, e.g., as yb=

[0158] The criterion of forming these clusters is the Euclidean distance between {y&} and each received symbol. The received symbol is placed in the bthcluster if its distance to yb is the smallest compared to the remaining 15 QAM symbols.

[0159] The difference eb t= yb+ yb ican be considered as an error vector relative to the centroid of the bthcluster. The EVM is defined as:

[0160] An alternate definition of the error vector is relative to the transmitted constellation point yb instead of the cluster center yb.

[0161] FIG. 7 shows the EVM for the two simulated systems (a) and (b) described in Section 2.2 and Section 2.3, respectively, for different pairs of M and N.

[0162] The main observation is that the EVM substantially reduces for the simulated system (b) as M and N are increased. In contrast, for the simulated system (a), the EVM obtained when M = N = 1 reduces when M is increased to 8 and N is increased to 2. However, for subsequent increases in M and N, no substantial EVM improvements are noticed.

[0163] FIG. 8 shows the 16-QAM received constellation points for the systems (a) and (b). The simulated scenario assumes OBO of 3 dB for both the systems. Two scenarios are simulated; M = 8 and N = 2; and M = 64 and N = 8. The result shows that the constellation clouds for system (b) have significantly diminished radii as M and N increase, whereas the radii of the constellation clusters do not exhibit a noticeable reduction for system (a).

[0164] The observations in FIG. 7 and FIG. 8 are extended in FIG. 9, which shows that the beamforming provides a small gain when M and N are increased from no-beamforming case (M = N = 1). However, system (a) performance ceases to improve, unlike system (b) which continues to exhibit performance improvement as M and N are increased.

[0165] Results in this section show the SER for 16-QAM as a function of per-symbol SNR, or average Es / No. The two columns in FIG. 10 are for system (a), and system (b), respectively. Similar to the performance trend in the prior section, we see here that the SER performance for system (a) in the left column improves when some beamforming is implemented, e.g., M = 8, N = , compared to no beamforming case, M = N = 1. However, there is no further improvement in the SER as the beamforming configuration is enhanced by increasing M and N. In the column on the right, system (b) shows an SER improvement compared to system (a) for larger values of M and N. The performance of system (b) exhibits a greater benefit as OBO is reduced, e.g., from 6dB to 2 dB. It is apparent that system performance is dominated by noise, but the impact of noise will reduce as SNR increases, and for very high values of SNR, i.e, above those shown in the figure, distortion from nonlinearity will then dominate.

[0166] The Total Degradation in the presence of nonlinearity is defined for a specific value of OBO of x dB and the probability of symbol error y;

[0167] Where the SNR in dB required to achieve the SER of y when the PAoperates at an OBO of x dB, and is the SNR in dB in the presence of ideal linear PA.

[0168] FIG. 11 shows the TD for system (a) and system (b). The performance improvement obtained by system (b) over system (a) is evident. System (a) also provides an improvement compared to M = N = 1 scenario. However, system (a), unlike system (b), fails to harvest further performance gains from increasing values of M and N.

[0169] The Adjacent Channel Leakage Ratio (ACLR) is defined as the ratio Pi / Po, where Pi is the measured signal power in-band and Po is the measured signal power in the two adjacent bands due to nonlinearity-induced spectral spillage. For the OFDM signal, the in-band power is measured by taking RMS of the desired OFDM signal at the output of the beamformer. Measurement of Po require special considerations. There are two alternatives as outlined below:

[0170] Employ orthogonal beamforming for different adjacent channel users. This ensures that the output of the desired user’s beamformer does not contain any contribution from the two adjacent users. Thus, the signal power measured over these adjacent bands is guaranteed to be due to thenonlinearity-induced spectral spillage. This method is used for the realistic beamformer detailed above.

[0171] Keep the adjacent bands empty. This method is used for the approach in Section 2.3 of randomizing the PA signals. This method is equivalent to nonorthogonal beamforming and the effect of orthogonal beamforming cannot be leveraged to measure the adjacent channel spectral leakage. Instead, the two bands adjacent to the OFDM signal of interest are kept devoid of a signal. In the absence of nonlinearity, the power Po measured over these two bands in the simulation is zero. The ACLR is evaluated by measuring the power in these empty adjacent bands at the output of the PA.

[0172] FIG. 12 shows the ACLR as a function of OBO for different numbers of array elements and the users. It is seen that the ACLR improves with increasing OBO as well as increasing number of array elements and number of users. However, for the realistic beamformer of Section 2.2, the improvement with an increasing number N of users saturates, whereas there is a steady increase with N for the randomized approach of Section 2.3.

[0173] FIG. 13 shows the time domain over 8000 OFDM samples at the input and output of the PA nonlinearity operating at OBO of 3 dB. A clipping effect due to the nonlinear compression can be observed. The Signal-to-Interference Ratio (SIR) can be computed and defined as SIR = _PS , where the PD Distortion Power Pnis defined as PD = E[\InputSig - OutputSig\2].

[0174] FIG. 14(a) shows the SDR as a function of OBO, and FIG. 14(b) as a function of antenna element index. With respect to OBO, the graph shows a steady improvement of SDR until OBO reaches 25 dB. Above this value little improvement is shown since the level of nonlinearity is very small. In terms of element index, SDR is showing to be almost constant, however after beamforming SDR is shown to become worse, shown in the graph as element 257.

[0175] Accordingly, as detailed above, an improvement can be expected in terms of EVM as a result of passing an OFDM signal through a non-linear amplifier when a beamformer and several users are included in the system. The EVM can be improved as a result of de-correlation between signals at the input to each PA. The results show that some improvement is apparent, but as a result of limited de-correlation between the signals the improvement is limited. A specific example shown can include an improvement of -2.5% of EVM (nominal level of -20% at 3dB OBO), which can be translated to an OBO reduction of -IdB. Furthermore, if random signals are presented, a more pronounced improvement is observed.

[0176] Throughout the specification, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases “in one embodiment” and “in some embodiments” as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments may be readily combined, without departing from the scope or spirit of the present disclosure.

[0177] In addition, the term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0178] As used herein, the terms “and” and “or” may be used interchangeably to refer to a set of items in both the conjunctive and disjunctive in order to encompass the full description of combinations and alternatives of the items. By way of example, a set of items may be listed withthe disjunctive “or”, or with the conjunction “and.” In either case, the set is to be interpreted as meaning each of the items singularly as alternatives, as well as any combination of the listed items.

[0179] It is understood that at least one aspect / functionality of various embodiments described herein can be performed in real-time and / or dynamically. As used herein, the term “real-time” is directed to an event / action that can occur instantaneously or almost instantaneously in time when another event / action has occurred. For example, the “real-time processing,” “real-time computation,” and “real-time execution” all pertain to the performance of a computation during the actual time that the related physical process (e.g., a user interacting with an application on a mobile device) occurs, in order that results of the computation can be used in guiding the physical process.

[0180] As used herein, the term “dynamically” and term “automatically,” and their logical and / or linguistic relatives and / or derivatives, mean that certain events and / or actions can be triggered and / or occur without any human intervention. In some embodiments, events and / or actions in accordance with the present disclosure can be in real-time and / or based on a predetermined periodicity of at least one of: nanosecond, several nanoseconds, millisecond, several milliseconds, second, several seconds, minute, several minutes, hourly, several hours, daily, several days, weekly, monthly, etc.

[0181] In some embodiments, exemplary inventive, specially programmed computing systems and platforms with associated devices are configured to operate in the distributed network environment, communicating with one another over one or more suitable data communication networks (e.g., the Internet, satellite, etc.) and utilizing one or more suitable data communication protocols / modes such as, without limitation, IPX / SPX, X.25, AX.25, AppleTalk(TM), TCP / IP (e.g., HTTP), near-field wireless communication (NFC), RFID, Narrow Band Internet of Things(NBIOT), 3G, 4G, 5G, GSM, GPRS, WiFi, WiMax, CDMA, satellite, ZigBee, and other suitable communication modes.

[0182] The material disclosed herein may be implemented in software or firmware or a combination of them or as instructions stored on a machine -readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any medium and / or mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others.

[0183] As used herein, the term “facility” identifies any combination of software components and / or hardware components which are designed / programmed / configured to manage / control other software and / or hardware components (such as the libraries, software development kits (SDKs), objects, etc.).

[0184] Examples of hardware elements may include processors, microprocessors, circuits, circuit elements (e.g., transistors, resistors, capacitors, inductors, and so forth), integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), logic gates, registers, semiconductor device, chips, microchips, chip sets, and so forth. In some embodiments, the one or more processors may be implemented as a Complex Instruction Set Computer (CISC) or Reduced Instruction Set Computer (RISC) processors; x86 instruction set compatible processors, multicore, or any other microprocessor or central processing unit (CPU). In various implementations,the one or more processors may be dual-core processor(s), dual-core mobile processor(s), and so forth.

[0185] Computer-related systems, computer systems, and systems, as used herein, include any combination of hardware, firmware and / or software. Examples of software may include software components, programs, applications, operating system software, middleware, firmware, software modules, routines, subroutines, functions, methods, procedures, software interfaces, application program interfaces (API), instruction sets, computer code, computer code segments, words, values, symbols, or any combination thereof. Determining whether an embodiment is implemented using hardware elements and / or software elements may vary in accordance with any number of factors, such as desired computational rate, power levels, heat tolerances, processing cycle budget, input data rates, output data rates, memory resources, data bus speeds and other design or performance constraints.

[0186] One or more aspects of at least one embodiment may be implemented by representative instructions stored on a machine-readable medium which represents various logic within the processor, which when read by a machine causes the machine to fabricate logic to perform the techniques described herein. Such representations, known as “IP cores” may be stored on a tangible, machine readable medium and supplied to various customers or manufacturing facilities to load into the fabrication machines that make the logic or processor. Of note, various embodiments described herein may, of course, be implemented using any appropriate hardware and / or computing software languages (e.g., C++, Objective-C, Swift, Java, JavaScript, Python, Perl, QT, etc.).

[0187] In some embodiments, one or more of illustrative computer-based systems or platforms of the present disclosure may include or be incorporated, partially or entirely into at least one personalcomputer (PC), laptop computer, ultra-laptop computer, tablet, touch pad, portable computer, handheld computer, palmtop computer, personal digital assistant (PDA), cellular telephone, combination cellular telephone / PDA, television, smart device (e.g., smart phone, smart tablet or smart television), mobile internet device (MID), messaging device, data communication device, and so forth.

[0188] In some embodiments, as detailed herein, one or more of the computer-based systems of the present disclosure may obtain, manipulate, transfer, store, transform, generate, and / or output any digital object and / or data unit (e.g., from inside and / or outside of a particular application) that can be in any suitable form such as, without limitation, a file, a contact, a task, an email, a message, a map, an entire application (e.g., a calculator), data points, and other suitable data. In some embodiments, as detailed herein, one or more of the computer-based systems of the present disclosure may be implemented across one or more of various computer platforms such as, but not limited to: (1) FreeBSD, NetBSD, OpenBSD; (2) Linux; (3) Microsoft Windows™; (4) OpenVMS™; (5) OS X (MacOS™); (6) UNIX™; (7) Android; (8) iOS™; (9) Embedded Linux; (10) Tizen™; (11) WebOS™; (12) Adobe AIR™; (13) Binary Runtime Environment for Wireless (BREW™); (14) Cocoa™ (API); (15) Cocoa™ Touch; (16) Java™ Platforms; (17) JavaFX™; (18) QNX™; (19) Mono; (20) Google Blink; (21) Apple WebKit; (22) Mozilla Gecko™; (23) Mozilla XUL; (24) .NET Framework; (25) Silverlight™; (26) Open Web Platform; (27) Oracle Database; (28) Qt™; (29) SAP NetWeaver™; (30) Smartface™; (31) Vexi™; (32) Kubernetes™ and (33) Windows Runtime (WinRT™) or other suitable computer platforms or any combination thereof. In some embodiments, illustrative computer-based systems or platforms of the present disclosure may be configured to utilize hardwired circuitry that may be used in place of or in combination with software instructions to implement features consistent with principles of thedisclosure. Thus, implementations consistent with principles of the disclosure are not limited to any specific combination of hardware circuitry and software. For example, various embodiments may be embodied in many different ways as a software component such as, without limitation, a stand-alone software package, a combination of software packages, or it may be a software package incorporated as a “tool” in a larger software product.

[0189] In some embodiments, illustrative computer-based systems or platforms of the present disclosure may be configured to handle numerous concurrent communicators (e.g., users, devices, or other, or any combination thereof) that may be, but is not limited to, at least 1, at least 10, at least 100 (e.g., but not limited to, 100-999), at least 1,000 (e.g., but not limited to, 1,000-9,999 ), at least 10,000 (e.g., but not limited to, 10,000-99,999 ), at least 100,000 (e.g., but not limited to, 100,000-999,999), at least 1,000,000 (e.g., but not limited to, 1,000,000-9,999,999), at least 10,000,000 (e.g., but not limited to, 10,000,000-99,999,999), at least 100,000,000 (e.g., but not limited to, 100,000,000-999,999,999), at least 1,000,000,000 (e.g., but not limited to, 1,000,000,000-999,999,999,999), and so on.

[0190] In some embodiments, illustrative computer-based systems or platforms of the present disclosure may be configured to be utilized in various applications which may include, but not limited to, gaming, mobile-device games, video chats, video conferences, live video streaming, video streaming and / or augmented reality applications, mobile-device messenger applications, and others similarly suitable computer-device applications.

[0191] As used herein, the term “mobile electronic device,” or the like, may refer to any portable electronic device that may or may not be enabled with location tracking functionality (e.g., MAC address, Internet Protocol (IP) address, or the like). For example, a mobile electronic device caninclude, but is not limited to, a mobile phone, Personal Digital Assistant (PDA), Blackberry ™, Pager, Smartphone, or any other reasonable mobile electronic device.

[0192] As used herein, the term “user” shall have a meaning of at least one user. In some embodiments, the terms “user”, “subscriber” “consumer” or “customer” should be understood to refer to a user of an application or applications as described herein and / or a consumer of data supplied by a data provider. By way of example, and not limitation, the terms “user” or “subscriber” can refer to a person who receives data provided by the data or service provider over the Internet in a browser session, or can refer to an automated software application which receives the data and stores or processes the data.

[0193] The aforementioned examples are, of course, illustrative and not restrictive.

[0194] At least some aspects of the present disclosure will now be described with reference to the following numbered clauses.

[0195] Publications cited throughout this document are hereby incorporated by reference in their entirety. While one or more embodiments of the present disclosure have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art, including that various embodiments of the inventive methodologies, the illustrative systems and platforms, and the illustrative devices described herein can be utilized in any combination with each other. Further still, the various steps may be carried out in any desired order (and any desired steps may be added and / or any desired steps may be eliminated).

Claims

1. CLAIMSWhat is claimed is:

1. A method comprising:obtaining, by at least one signal processing device, a plurality of information-bearing carrier signals associated with a plurality of electronic communications to a plurality of endpoints, each information-bearing carrier signal of the plurality of information-bearing carrier signals having a different phase;filtering, by the at least one signal processing device, using a filter, each informationbearing carrier signal of the plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal of the plurality of information-bearing carrier signals so as to introduce a delay into each information-bearing carrier signal of the plurality of information-bearing carrier signals;wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals is randomly selected;wherein the delay of each information-bearing carrier signal of the plurality information-bearing carrier signals is sufficient to reduce correlation between the plurality of information-bearing carrier signals to mitigate a peak-to-average power ratio to below a threshold level; andamplifying, by the at least one signal processing device using at least one amplifier, the plurality of information-bearing carrier signals in accordance with the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals.

2. The method of claim 1, further comprising:filtering, by the at least one signal processing device, using an inverse filter, upon the amplifying, the plurality of information-bearing carrier signals based at least in part on the phase of each information-bearing carrier signal;wherein the inverse filter is inverse to the filter so as to remove the delay from each information-bearing carrier signal of the plurality of information-bearing carrier signals.

3. The method of claim 1, wherein the filter is an all pass filter.

4. The method of claim 1 , wherein the filter is a digital filter.

5. The method of claim 1, wherein splitting the information-bearing carrier signal into a plurality of information-bearing carrier signals comprises:utilizing, by the at least one signal processing device, at least one beamformer to beamform the plurality of information-bearing carrier signals;wherein the filter is configured to filter the plurality information-bearing carrier signals after the at least one beamformer.

6. The method of claim 1, further comprising:controlling, by the at least one signal processing device, at least one antenna to transmit the plurality of information-bearing carrier signals.

7. The method of claim 1, wherein the at least one amplifier comprises at least one non-linear amplifier.

8. The method of claim 1, wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals comprises at least one half of a symbol in length.

9. A method comprising:filtering, by the at least one signal processing device, using a filter, each informationbearing carrier signal of a plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal of the plurality of information-bearing carrier signals so as to introduce a delay into each information-bearing carrier signal of the plurality of information-bearing carrier signals;wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals is randomly selected;wherein the delay of each information-bearing carrier signal of the plurality information-bearing carrier signals is sufficient to decorrelate the plurality of information-bearing carrier signals;wherein each information-bearing carrier signals comprises data associated with an electronic communication;amplifying, by the at least one signal processing device using at least one amplifier, the plurality of information-bearing carrier signals in accordance with the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals; andfiltering, by the at least one signal processing device, using an inverse filter, upon the amplifying, the plurality of information-bearing carrier signals based at least in part on the phase of each information-bearing carrier signal;wherein the inverse filter is inverse to the filter so as to remove the delay from each information-bearing carrier signal of the plurality of information-bearing carrier signals.

10. The method of claim 9, wherein the filter is an all pass filter.

11. The method of claim 9, wherein the filter is a digital filter.

12. The method of claim 9, wherein splitting the information-bearing carrier signal into a plurality of information-bearing carrier signals comprises:utilizing, by the at least one signal processing device, at least one beamformer to beamform the plurality of information-bearing carrier signals;wherein the filter is configured to filter the plurality information-bearing carrier signals after the at least one beamformer.

13. The method of claim 9, further comprising:controlling, by the at least one signal processing device, at least one antenna to transmit the plurality of information-bearing carrier signals.

14. The method of claim 9, wherein the at least one amplifier comprises at least one non-linear amplifier.

15. The method of claim 9, wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals comprises at least one half of a symbol in length.

16. A signal processing apparatus comprising:at least one filter configured to filter each information-bearing carrier signal of a plurality of information-bearing carrier signals based on a phase of each information-bearing carrier signal of the plurality of information-bearing carrier signals so as to introduce a delay into each information-bearing carrier signal of the plurality of information-bearing carrier signals;wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals is randomly selected;wherein the delay of each information-bearing carrier signal of the plurality information-bearing carrier signals is sufficient to decorrelate the plurality of information-bearing carrier signals;wherein each information-bearing carrier signals comprises data associated with an electronic communication;at least one amplifier configured to amplify the plurality of information-bearing carrier signals in accordance with the delay of each information-bearing carrier signal of the plurality of information -bearing carrier signals; andat least one inverse filter configured to, upon the amplifying, the plurality of informationbearing carrier signals based at least in part on the phase of each information-bearing carrier signal;wherein the inverse filter is inverse to the filter so as to remove the delay from each information-bearing carrier signal of the plurality of information-bearing carrier signals.

17. The signal processing apparatus of claim 16, wherein the filter is an all pass filter.

18. The signal processing apparatus of claim 16, further comprising at least one beamformer configured to beamform the plurality of information-bearing carrier signals prior to the at least one filter.

19. The signal processing apparatus of claim 16, further comprising at least one antenna configured to transmit the plurality of information-bearing carrier signals.

20. The signal processing apparatus of claim 16, wherein the delay of each information-bearing carrier signal of the plurality of information-bearing carrier signals comprises at least one half of a symbol in length.

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