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This thesis project investigates the topic of joint optimization for crest factor reduction and digital predistortion blocks, which are used for digital correction of analogue impairments in digital radio front ends. The work first investigates the effects of joint parameter variation of the above blocks on the global performance and computational cost of the digital chain, given reference CFR and DPD algorithms. Then it proposes a method for joint optimization of said CFR and DPD parameters, based on a constrained optimization of a composite target function. The constraints of this optimization problem ensure that the solution meets the requirements on out-of-band emissions and signal quality, while the target function values solutions that outperform these requirements and are computationally cheaper to implement. The solutions of such an optimization problem are determined with the help of simulations. The simulations provide estimated performance metrics on signal quality and out-of-band emissions as well as estimated computational cost for a given parameter configuration. The results show that the proposed optimization can guide the selection of parameters for multiple blocks of the DFE while ensuring applicability in different use-cases via an easily configurable target function., Tänk om man kunde titta ut genom sitt fönster och se det osynliga som gör vårt moderna liv möjligt. Blipp!, bussbiljettens utgångsdatum är om elva dagar, grön signal. Swish!, saldo minus 29 kr, betalningen går igenom i glasskiosken. Pling!, "-Ring mig när du kan, jag har något roligt att berätta!". Varje ögonblick färdas oräkneligt många signaler i ljusets hastighet mitt framför näsan på oss utan att vi märker något. Allt som skedde utanför fönstret möjligjordes genom att elektromagnetiska vågor färdades mellan mobiltelefoner och sändare i master. När en mast sänder ut en signal måste den förstärkas för att den ska nå mottagaren. Problemet är att förstärkare ofta beter sig oberäkneligt och förvränger signalen. Ju högre spänning förstärkarens insignal har desto värre blir dessa förvrängningar. Om man har otur försämras signalens kvalité till den grad att datan den bär på blir oläslig. Bruset den orsakar kan även störa signaler i grannkanaler, därför måste utsignalen uppfylla kvalitétskrav som bestäms av myndigheter. Man skulle kunna undvika detta genom att mata förstärkaren med en svagare signal, men då försämras förstärkarens verkningsgrad och räckvidd väsentligt. För att kringå denna avvägning mellan signalkvalité och verkningsgrad kan man manipulera signalen på ett sätt som kompenserar för förstärkarens brister. Det finns många metoder att göra detta på och detta examensarbete har undersökt kombinerad digital förförvrängning och klippfiltrering. Klippfiltrering sätter ett tröskelvärde och klipper bort den delen av insignalen vars spänning överskrider det. Dessa spänningstoppar som klipptes bort var den delen av signalen som orsakade mest förvrängnining och brus i förstärkaren. Klippandet i sig orsakar också brus men denna bruskällan undgås genom att man filtrerar den avklippta delen av signalen och subtraherar den från den ursprungliga. Ju lägre tröskelvärde, desto högre spänning kan man mata förstärkaren med, men är det för lågt så kan signalen förändras så mycke

Radio frequency (RF) power amplifiers (PA) are efficiently linearized by adaptive digital predistortion (DPD). However, performance of DPD is severely degraded in presence of transmitter’s frequency-selective in-phase/quadrature (I/Q) imbalance. We propose DPD/IQ method that compensates the effects of transmitter I/Q imbalance and PA nonlinearity, which is dedicated for implementation in low-cost software radio defined (SDR) cellular base stations. The advantage of DPD/IQ is low complexity in terms of reduced number of DPD coefficients which provides significant savings of FPGA resources. The DPD/IQ has been evaluated after method has been implemented in SDR board. Measured results clearly demonstrate efficient compensation of PA and transceiver impairments enabling transmission of wide bandwidth waveforms and realization of sophisticated modulation schemes. Improvement in image rejection ratio of 10-15dB is achieved. Considering compensation of PA nonlinearities, the ACPR at PA output is decreased by 15dBc.

Radio frequency (RF) power amplifiers (PA) are efficiently linearized by adaptive digital predistortion (DPD). However, performance of DPD is severely degraded in presence of transmitter’s frequency-selective in-phase/quadrature (I/Q) imbalance. We propose DPD/IQ method that compensates the effects of transmitter I/Q imbalance and PA nonlinearity, which is dedicated for implementation in low-cost software radio defined (SDR) cellular base stations. The advantage of DPD/IQ is low complexity in terms of reduced number of DPD coefficients which provides significant savings of FPGA resources. The DPD/IQ has been evaluated after method has been implemented in SDR board. Measured results clearly demonstrate efficient compensation of PA and transceiver impairments enabling transmission of wide bandwidth waveforms and realization of sophisticated modulation schemes. Improvement in image rejection ratio of 10-15dB is achieved. Considering compensation of PA nonlinearities, the ACPR at PA output is decreased by 15dBc.

Radio frequency (RF) power amplifiers (PA) are efficiently linearized by adaptive digital predistortion (DPD). However, performance of DPD is severely degraded in presence of transmitter’s frequency-selective in-phase/quadrature (I/Q) imbalance. We propose DPD/IQ method that compensates the effects of transmitter I/Q imbalance and PA nonlinearity, which is dedicated for implementation in low-cost software radio defined (SDR) cellular base stations. The advantage of DPD/IQ is low complexity in terms of reduced number of DPD coefficients which provides significant savings of FPGA resources. The DPD/IQ has been evaluated after method has been implemented in SDR board. Measured results clearly demonstrate efficient compensation of PA and transceiver impairments enabling transmission of wide bandwidth waveforms and realization of sophisticated modulation schemes. Improvement in image rejection ratio of 10-15dB is achieved. Considering compensation of PA nonlinearities, the ACPR at PA output is decreased by 15dBc.

Radio frequency (RF) power amplifiers (PA) are efficiently linearized by adaptive digital predistortion (DPD). However, performance of DPD is severely degraded in presence of transmitter’s frequency-selective in-phase/quadrature (I/Q) imbalance. We propose DPD/IQ method that compensates the effects of transmitter I/Q imbalance and PA nonlinearity, which is dedicated for implementation in low-cost software radio defined (SDR) cellular base stations. The advantage of DPD/IQ is low complexity in terms of reduced number of DPD coefficients which provides significant savings of FPGA resources. The DPD/IQ has been evaluated after method has been implemented in SDR board. Measured results clearly demonstrate efficient compensation of PA and transceiver impairments enabling transmission of wide bandwidth waveforms and realization of sophisticated modulation schemes. Improvement in image rejection ratio of 10-15dB is achieved. Considering compensation of PA nonlinearities, the ACPR at PA output is decreased by 15dBc.

Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. Therefore, this thesis focuses on the characterization and compensation of these hardware impairments in RF SISO and MIMO transmitters. PA distortions are often compensated using the Volterra series, but it suffers from high computational complexity. Therefore, a non-parametric method based on density estimation has been proposed in this thesis to estimate the PA transfer function, from which pruned Volterra models can be developed. The method is validated for a Doherty PA and achieves competitive error performance at a lower complexity than its competitors. For MIMO transmitters, a characterization technique that uses multitone excitation signals has been proposed. Multitone signals yield non-overlapping tones at the outputs of the MIMO Volterra kernels. These kernel outputs are used to identify the dominant crosstalk impairments, from which block structure and base-band behavioral models are developed. The method is validated for 2x2 and 3x3 MIMO transmitters and it is shown that the derived models achieve a better complexity accuracy trade-off than the other pruned MIMO Volterra models considered in this thesis. Finally, the thesis presents compensation models for joint static I/Q imbalance and MIMO PA distortions based on conjugate pair and real-valued basis functions. The models are augmented with sub-sample resolution to compensate for dynamic I/Q imbalance distortions. The proposed models are validated for a 2x2 RF MIMO transmitter and achieve a better complexity accuracy trade-off than the other state-of-the-art models considered in this thesis., QC 20180921

Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. Therefore, this thesis focuses on the characterization and compensation of these hardware impairments in RF SISO and MIMO transmitters. PA distortions are often compensated using the Volterra series, but it suffers from high computational complexity. Therefore, a non-parametric method based on density estimation has been proposed in this thesis to estimate the PA transfer function, from which pruned Volterra models can be developed. The method is validated for a Doherty PA and achieves competitive error performance at a lower complexity than its competitors. For MIMO transmitters, a characterization technique that uses multitone excitation signals has been proposed. Multitone signals yield non-overlapping tones at the outputs of the MIMO Volterra kernels. These kernel outputs are used to identify the dominant crosstalk impairments, from which block structure and base-band behavioral models are developed. The method is validated for 2x2 and 3x3 MIMO transmitters and it is shown that the derived models achieve a better complexity accuracy trade-off than the other pruned MIMO Volterra models considered in this thesis. Finally, the thesis presents compensation models for joint static I/Q imbalance and MIMO PA distortions based on conjugate pair and real-valued basis functions. The models are augmented with sub-sample resolution to compensate for dynamic I/Q imbalance distortions. The proposed models are validated for a 2x2 RF MIMO transmitter and achieve a better complexity accuracy trade-off than the other state-of-the-art models considered in this thesis., QC 20180921

Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. Therefore, this thesis focuses on the characterization and compensation of these hardware impairments in RF SISO and MIMO transmitters. PA distortions are often compensated using the Volterra series, but it suffers from high computational complexity. Therefore, a non-parametric method based on density estimation has been proposed in this thesis to estimate the PA transfer function, from which pruned Volterra models can be developed. The method is validated for a Doherty PA and achieves competitive error performance at a lower complexity than its competitors. For MIMO transmitters, a characterization technique that uses multitone excitation signals has been proposed. Multitone signals yield non-overlapping tones at the outputs of the MIMO Volterra kernels. These kernel outputs are used to identify the dominant crosstalk impairments, from which block structure and base-band behavioral models are developed. The method is validated for 2x2 and 3x3 MIMO transmitters and it is shown that the derived models achieve a better complexity accuracy trade-off than the other pruned MIMO Volterra models considered in this thesis. Finally, the thesis presents compensation models for joint static I/Q imbalance and MIMO PA distortions based on conjugate pair and real-valued basis functions. The models are augmented with sub-sample resolution to compensate for dynamic I/Q imbalance distortions. The proposed models are validated for a 2x2 RF MIMO transmitter and achieve a better complexity accuracy trade-off than the other state-of-the-art models considered in this thesis., QC 20180921

Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. Therefore, this thesis focuses on the characterization and compensation of these hardware impairments in RF SISO and MIMO transmitters. PA distortions are often compensated using the Volterra series, but it suffers from high computational complexity. Therefore, a non-parametric method based on density estimation has been proposed in this thesis to estimate the PA transfer function, from which pruned Volterra models can be developed. The method is validated for a Doherty PA and achieves competitive error performance at a lower complexity than its competitors. For MIMO transmitters, a characterization technique that uses multitone excitation signals has been proposed. Multitone signals yield non-overlapping tones at the outputs of the MIMO Volterra kernels. These kernel outputs are used to identify the dominant crosstalk impairments, from which block structure and base-band behavioral models are developed. The method is validated for 2x2 and 3x3 MIMO transmitters and it is shown that the derived models achieve a better complexity accuracy trade-off than the other pruned MIMO Volterra models considered in this thesis. Finally, the thesis presents compensation models for joint static I/Q imbalance and MIMO PA distortions based on conjugate pair and real-valued basis functions. The models are augmented with sub-sample resolution to compensate for dynamic I/Q imbalance distortions. The proposed models are validated for a 2x2 RF MIMO transmitter and achieve a better complexity accuracy trade-off than the other state-of-the-art models considered in this thesis., QC 20180921

Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. Therefore, this thesis focuses on the characterization and compensation of these hardware impairments in RF SISO and MIMO transmitters. PA distortions are often compensated using the Volterra series, but it suffers from high computational complexity. Therefore, a non-parametric method based on density estimation has been proposed in this thesis to estimate the PA transfer function, from which pruned Volterra models can be developed. The method is validated for a Doherty PA and achieves competitive error performance at a lower complexity than its competitors. For MIMO transmitters, a characterization technique that uses multitone excitation signals has been proposed. Multitone signals yield non-overlapping tones at the outputs of the MIMO Volterra kernels. These kernel outputs are used to identify the dominant crosstalk impairments, from which block structure and base-band behavioral models are developed. The method is validated for 2x2 and 3x3 MIMO transmitters and it is shown that the derived models achieve a better complexity accuracy trade-off than the other pruned MIMO Volterra models considered in this thesis. Finally, the thesis presents compensation models for joint static I/Q imbalance and MIMO PA distortions based on conjugate pair and real-valued basis functions. The models are augmented with sub-sample resolution to compensate for dynamic I/Q imbalance distortions. The proposed models are validated for a 2x2 RF MIMO transmitter and achieve a better complexity accuracy trade-off than the other state-of-the-art models considered in this thesis., QC 20180921

Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. Therefore, this thesis focuses on the characterization and compensation of these hardware impairments in RF SISO and MIMO transmitters. PA distortions are often compensated using the Volterra series, but it suffers from high computational complexity. Therefore, a non-parametric method based on density estimation has been proposed in this thesis to estimate the PA transfer function, from which pruned Volterra models can be developed. The method is validated for a Doherty PA and achieves competitive error performance at a lower complexity than its competitors. For MIMO transmitters, a characterization technique that uses multitone excitation signals has been proposed. Multitone signals yield non-overlapping tones at the outputs of the MIMO Volterra kernels. These kernel outputs are used to identify the dominant crosstalk impairments, from which block structure and base-band behavioral models are developed. The method is validated for 2x2 and 3x3 MIMO transmitters and it is shown that the derived models achieve a better complexity accuracy trade-off than the other pruned MIMO Volterra models considered in this thesis. Finally, the thesis presents compensation models for joint static I/Q imbalance and MIMO PA distortions based on conjugate pair and real-valued basis functions. The models are augmented with sub-sample resolution to compensate for dynamic I/Q imbalance distortions. The proposed models are validated for a 2x2 RF MIMO transmitter and achieve a better complexity accuracy trade-off than the other state-of-the-art models considered in this thesis.

Linearity and high efficiency are crucial requirements for any power amplifier. However, power amplifiers have high efficiency levels when they are in non-linear regions. To overcome this issue there have been many suggestions in literature, one of the most successful methods is digital predistortion method. Digital predistortion (DPD) method’s low resource usage and fairly easy algorithm draws a lot of researcher’s attention. Many different methods are suggested for DPD algorithms. Volterra series based methods draws even more attention due to its flexibility and easy implementation. However, deciding which method to use for DPD purposes is not completed even when Volterra series based method is chosen. There are many different Volterra series based methods which differ from each other. This paper examines 5 different Volterra based methods for DPD purposes and tests them in 2 different PAs with LTE signals. Also forward behavioral modelling performance of these 5 methods are also examined for each PA with same signals. In chapter 1 needed theoretical information is explained about power amplifier characteristics. In chapter 2, the five chosen methods are examined in detail and corresponding parameters are explained. In chapter 3, forward behavioral modelling setup and the way to model power amplifiers is explained. In chapter 4, setup and the digital predistortion algorithms are explained. In the 5th chapter the results of both behavioral modelling and DPD is shown and comments on the results are given.

This paper contains supporting derivations for the paperMemory Polynomial Baseband Modeling of RF Power Am-plifiers. All references to numbered equations, propositionsand assumptions are to the corresponding number inMemoryPolynomial Baseband Modeling of RF Power Amplifiers., VR radiomättekink för svagt ickelinjära system

This paper contains supporting derivations for the paperMemory Polynomial Baseband Modeling of RF Power Am-plifiers. All references to numbered equations, propositionsand assumptions are to the corresponding number inMemoryPolynomial Baseband Modeling of RF Power Amplifiers., VR radiomättekink för svagt ickelinjära system

This paper contains supporting derivations for the paperMemory Polynomial Baseband Modeling of RF Power Am-plifiers. All references to numbered equations, propositionsand assumptions are to the corresponding number inMemoryPolynomial Baseband Modeling of RF Power Amplifiers., VR radiomättekink för svagt ickelinjära system

This paper contains supporting derivations for the paperMemory Polynomial Baseband Modeling of RF Power Am-plifiers. All references to numbered equations, propositionsand assumptions are to the corresponding number inMemoryPolynomial Baseband Modeling of RF Power Amplifiers., VR radiomättekink för svagt ickelinjära system

This paper contains supporting derivations for the paperMemory Polynomial Baseband Modeling of RF Power Am-plifiers. All references to numbered equations, propositionsand assumptions are to the corresponding number inMemoryPolynomial Baseband Modeling of RF Power Amplifiers., VR radiomättekink för svagt ickelinjära system