On the efficiency of PAPR reduction schemes deployed for DRM systems

Digital Radio Mondiale (DRM) is the universally, openly standardized digital broadcasting system for all frequencies including LW, MW, and SW as well as VHF bands. Alongside providing high audio quality to listeners, DRM satisfies technological requirements posed by broadcasters, manufacturers and regulatory authorities and thus bears a great potential for the future of global radio. One of the key issues here concerns green broadcasting. Facing the need for high-power transmitters to cover wide areas, there is room for improvement concerning the power efficiency of DRM-transmitters. A major drawback of DRM is its high peak-to-average power ratio (PAPR) due to the applied transmission technology based on Orthogonal Frequency Division Multiplexing (OFDM), which results in non-linearities in the emitted signal, low power efficiency, and high costs of transmitters. To overcome this, numerous schemes have been investigated for reducing PAPR in OFDM systems. In this paper, we review and analyze various technologies to reduce PAPR providing that the technical feasibility and DRM-specific system architecture and edge conditions regarding the system performance in terms of modulation error rate, compliance with frequency mask, and synchronization efficiency are ensured. All evaluations are carried out with I/Q signals which are monitored in real operation to present the actual performance of proposed PAPR techniques. Subsequently, the capability of the best approach is evaluated via measurements on a DRM test platform, where achieved transmit power gain of 10 dB is shown. According to our evaluation results, PAPR reduction schemes based on active constellation extension followed by a filter prove to be promising towards practical realization of power-efficient transmitters. © 2016, The Author(s)

A Low-Complexity SLM PAPR Reduction Scheme for OFDMA

In orthogonal frequency division multiplexing (OFDM) systems, selected mapping (SLM) techniques are widely used to minimize the peak to average power ratio (PAPR). The candidate signals are generated in the time domain by linearly mixing the original time-domain transmitted signal with numerous cyclic shift equivalents to reduce the amount of Inverse Fast Fourier Transform (IFFT) operations in typical SLM systems. The weighting factors and number of cyclic shifts, on the other hand, should be carefully chosen to guarantee that the elements of the appropriate frequency domain phase rotation vectors are of equal magnitude. A low-complexity expression is chosen from among these options to create the proposed low-complexity scheme, which only requires one IFFT. In comparison to the existing SLM technique, the new SLM scheme achieves equivalent PAPR reduction performance with significantly less computing complexity. MATLAB tool is used for simulating the proposed work

A SURVEY OF PAPR REDUCTION IN OFDM SIGNALS

  In Radio waves, the digital data can be transmitted using Burst number of data using OFDM technique. So only an OFDM Technique is called attractive modulation techniques. In this OFDM signal transmission having so many disadvantages, one of the main disadvantages is a Peak average power which is due to combination of sinusoidal leads to high peak-to power ratio (PAPR).Due to High PAPR, which leads to poor (i.e) degrades the signal performance of power amplifier in transmission, this PAPR can be reduce using some of the following technique like, there are Clipping, Coding, Partial transmit sequence (PTS), Sequential Mapping(SM), Tone reservation (TR), Tone injection (TI), Interleaving, Nonlinear companding transform, & Hadamard transform etc.Various technique are available to reduce the Peak power and discuss detail about the merits and demerits .Â

A Low-Complexity SLM PAPR Reduction Scheme for OFDMA

In orthogonal frequency division multiplexing (OFDM) systems, selected mapping (SLM) techniques are widely used to minimize the peak to average power ratio (PAPR). The candidate signals are generated in the time domain by linearly mixing the original time-domain transmitted signal with numerous cyclic shift equivalents to reduce the amount of Inverse Fast Fourier Transform (IFFT) operations in typical SLM systems. The weighting factors and number of cyclic shifts, on the other hand, should be carefully chosen to guarantee that the elements of the appropriate frequency domain phase rotation vectors are of equal magnitude. A low-complexity expression is chosen from among these options to create the proposed low-complexity scheme, which only requires one IFFT. In comparison to the existing SLM technique, the new SLM scheme achieves equivalent PAPR reduction performance with significantly less computing complexity. MATLAB tool is used for simulating the proposed work

PAPR Analysis in OFDM-IQ-IM Systems

One of the key disadvantages of OFDM system, implemented already in 4G and 5G is high PAPR. For this reason, it is very important to evaluate the PAPR performance of any potential multiplexing technique candidate for upcoming generations. Due to the superior performance over OFDM considering BER performance, spectral efficiency, energy efficiency, OFDM-IQ-IM is one of the promising multiplexing techniques for upcoming generations of wireless technology. Therefore, the PAPR performance of OFDM-IQ-IM system has been analysed here. In deterministic approach, subcarriers are considered to be modulated by symbols with highest power and the upper limit of the PAPR of OFDM-IQ-IM system has been formulated. Using statistical distribution, a probabilistic approach has been taken to determine the PAPR performance of the OFDM-IQ-IM and OFDM-IM systems. The distribution of PAPR of OFDM-IQ-IM and OFDM-IM systems has been evaluated considering the discrete time baseband signals for both in-phase and quadrature components as independent Gaussian random variables. A comparative analysis of the PAPR of OFDM, OFDM-IM and OFDM-IQ-IM systems has been made in both deterministic and probabilistic approach. Thus improved PAPR performance has been noticed in OFDM-IQ-IM system compared to OFDM-IM and OFDM systems for same spectral efficiency

LTE Adaptation for Mobile Broadband Satellite Networks

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An Overview of the ATSC 3.0 Physical Layer Specification

"(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")This paper provides an overview of the physical layer specification of Advanced Television Systems Committee (ATSC) 3.0, the next-generation digital terrestrial broadcasting standard. ATSC 3.0 does not have any backwards-compatibility constraint with existing ATSC standards, and it uses orthogonal frequency division multiplexing-based waveforms along with powerful low-density parity check (LDPC) forward error correction codes similar to existing state-of-the-art. However, it introduces many new technological features such as 2-D non-uniform constellations, improved and ultra-robust LDPC codes, power-based layered division multiplexing to efficiently provide mobile and fixed services in the same radio frequency (RF) channel, as well as a novel frequency pre-distortion multiple-input single-output antenna scheme. ATSC 3.0 also allows bonding of two RF channels to increase the service peak data rate and to exploit inter-RF channel frequency diversity, and to employ dual-polarized multiple-input multiple-output antenna system. Furthermore, ATSC 3.0 provides great flexibility in terms of configuration parameters (e.g., 12 coding rates, 6 modulation orders, 16 pilot patterns, 12 guard intervals, and 2 time interleavers), and also a very flexible data multiplexing scheme using time, frequency, and power dimensions. As a consequence, ATSC 3.0 not only improves the spectral efficiency and robustness well beyond the first generation ATSC broadcast television standard, but also it is positioned to become the reference terrestrial broadcasting technology worldwide due to its unprecedented performance and flexibility. Another key aspect of ATSC 3.0 is its extensible signaling, which will allow including new technologies in the future without disrupting ATSC 3.0 services. This paper provides an overview of the physical layer technologies of ATSC 3.0, covering the ATSC A/321 standard that describes the so-called bootstrap, which is the universal entry point to an ATSC 3.0 signal, and the ATSC A/322 standard that describes the physical layer downlink signals after the bootstrap. A summary comparison between ATSC 3.0 and DVB-T2 is also provided.Fay, L.; Michael, L.; Gómez Barquero, D.; Ammar, N.; Caldwell, MW. (2016). An Overview of the ATSC 3.0 Physical Layer Specification. IEEE Transactions on Broadcasting. 62(1):159-171. doi:10.1109/TBC.2015.2505417S15917162

Simplified Levenberg-Marquardt Algorithm based PAPR Reduction for OFDM System with Neural Network

In recent years, OFDM is the key transmission technique in the communication system. This is because of the high channel estimation, strong against multipath fading and increased spectral efficiency. Because of the independently modulated subcarriers, the Peak to Average Power Ratio (PAPR) is very high in OFDM systems. Previously we use a number of PAPR reduction schemes using clipping, adding windows etc. But in these methods we cannot achieve the optimum reduction or the BER performance is high or the system is very complex. On considering the BER performance and system complexity we employ a new method based on the Neural Network (NN). In this new method we achieve significant PAPR reduction with great BER improvement and complexity reduction. In the simulations we seen that the PAPR reduction and BER performance are very good. DOI: 10.17762/ijritcc2321-8169.15080

PAR-Aware Large-Scale Multi-User MIMO-OFDM Downlink

We investigate an orthogonal frequency-division multiplexing (OFDM)-based downlink transmission scheme for large-scale multi-user (MU) multiple-input multiple-output (MIMO) wireless systems. The use of OFDM causes a high peak-to-average (power) ratio (PAR), which necessitates expensive and power-inefficient radio-frequency (RF) components at the base station. In this paper, we present a novel downlink transmission scheme, which exploits the massive degrees-of-freedom available in large-scale MU-MIMO-OFDM systems to achieve low PAR. Specifically, we propose to jointly perform MU precoding, OFDM modulation, and PAR reduction by solving a convex optimization problem. We develop a corresponding fast iterative truncation algorithm (FITRA) and show numerical results to demonstrate tremendous PAR-reduction capabilities. The significantly reduced linearity requirements eventually enable the use of low-cost RF components for the large-scale MU-MIMO-OFDM downlink.Comment: To appear in IEEE Journal on Selected Areas in Communication

Performance of OPS-SAP technique for PAPR reduction in IEEE 802.11p scenarios

Vehicular Ad Hoc Networks (VANETs) are wireless networks that emerged thanks to the rapid evolution of wireless technologies and the automotive industry. The IEEE 802.11p standard is part of a group of standards related to all layers of protocols for Wireless Access in Vehicular Environment (WAVE) communications, which defines Medium Access Control (MAC) and Physical (PHY) levels. The PHY layer of IEEE 802.11p is essentially based on Orthogonal Frequency Division Multiplexing (OFDM) due to its advantages. However, OFDM signal suffers from high Peak-to-Average Power Ratio (PAPR) at the transmitter side, which causes a significant power efficiency penalty. An efficient peak power reduction technique is Simple Amplitude Predistortion aided by Orthogonal Pilot Sequences (OPS-SAP), which consists in moving certain outer constellation points of the frequency-domain OFDM symbol. In this paper, we propose the application of this OPS-SAP scheme in the IEEE 802.11p scenario, and, moreover, its evaluation under a complete PHY layer.This work has been supported by the Spanish National Projects GRE3N-SYST (TEC2011-29006-C03-03) and ELISA (TEC2014-59255-C3-3-R) and also by Escuela Politécnica a Nacional (Ecuador) by PII-DETRI-01-2016 Project