212723649
PAPR reduction performance of bat algorithm in OFDM systems
The progression in technology requires improved modulation techniques for wideband digital communication systems. Orthogonal frequency division multiplexing is efficacious systems to fulfill high-speed data transmissions needs. However, high peak-to-average power ratio (PAPR) is one of the significant limitations on the performance and power efficiency of OFDM systems. Due to industrial and scientific relevance, the assessment of the PAPR reduction has become popular subject in the current decade. This study presents the combination of bat algorithm with partial transmit sequence scheme as an efficient PAPR reduction method with an alleviated computational load. A set of simulations with different partial transmit sequence schemes are performed to comparatively evaluate the PAPR reduction performance of the partial transmit sequence based on bat algorithm scheme in OFDM system. The simulation results elucidate that BA-PTS scheme can provides better PAPR reduction performance with less computational load.
123640406
Partial approximate gradient constellation for PAPR reduction in OFDM signals
In this paper, a combinational approach for peak-to-average power ratio reduction in orthogonal frequency division multiplexing is proposed. The key idea of the proposed scheme is to apply partial transmit sequence and approximate gradient project schemes in parallel on two equal halves of subcarrier in an OFDM standard. On one half, partial transmit sequence minimises the PAPR of OFDM symbols through disjoint sub blocks and optimised phase factors, whereas for the other half, approximate gradient project extends the outer constellation points of OFDM symbols dynamically within margin-preserving constraints to reduce the peak magnitude of symbols. The simulation results show that proposed schemes reduces the PAPR as compared to other conventional schemes and maintains the bit error rate performance of the system especially at low signal to noise ratio. Moreover, the proposed method improves the data rate and also reduces the computational complexity when compared with partial transmit sequence scheme.
12968956
Peak-to-Average Power Ratio Reduction of OFDM signals Using Improved PTS Scheme with Low Computational Complexity
In wireless communication, parallel transmission of symbols using multi carriers is applied to achieve high efficiency in terms of throughput and better transmission quality. Orthogonal Frequency Division Multiplexing (OFDM) is one of the techniques for parallel transmission. It effectively mitigates the effect on performance due to Intersymbol Interference and delay spread caused by wireless medium. However high peak to average power ratio (PAPR) is a major demerit of OFDM system. High PAPR leads to increased complexity of circuit and reduced efficiency of RF amplifier. Partial Transmit Sequence (PTS) is one of the most promising techniques for PAPR reduction. In conventional PTS scheme the computation of optimal phase factors necessitates exhaustive searching of all possible and allowable phase factors, this leads to exponential increase of computation complexity in terms of complex additions and multiplications as number of subblock increases. In this paper by exploiting correlation among various candidate phase factors a novel scheme is proposed here which reduces the computation complexity by tremendous margin and at the same time maintaining same PAPR reduction as conventional PTS scheme. OFDM signal Implemented here complies with IEEE 802.11 a standard.
15089878
Diversity performance of precoded OFDM with MMSE equalization
Two sets of bit error rate (BER) lower bounds for precoded orthogonal frequency division multiplexing (OFDM) systems using minimum mean square error (MMSE) equalization over frequency-selective multipath fading channels are evaluated by Monte Carlo method in this paper. The first set represents the best performance under different data group sizes used for precoding, whereas the second set represents the best performance under different channel multipath diversity orders. These performance bounds can serve as the guidelines for system designers to decide proper data group sizes for precoded OFDM systems in order to achieve better trade-off between system performance and complexity. Numerical results also confirm the usefulness of these lower bounds for practical OFDM systems.
40760502
PTS-clipping method to reduce the PAPR in ROF-OFDM system
In this paper, a novel method combined the linear and nonlinear methods, named as partial transmit sequence followed by clipping (PTS-Clipping), is proposed to reduce the peak-to-average power ratio (PAPR) of radio over fiber and orthogonal frequency division multiplexing (ROF-OFDM) system. The main technique of this method is clipping the processed signal whose probability of the peak value has been reduced by PTS technique. Then the PAPR value will be further reduced. It will bring in slight change to the BER performance between with and without clipping. We know that both the ROF and OFDM techniques are key issues of the next generation network. Reduce the PAPR of OFDM is a necessary work. The simulation results show the feasibility of this method.
109944900
Block coding scheme for reduction of peak to mean envelope power ratio of multicarrier transmission schemes
A block coding scheme for the reduction of the peak to mean envelope power ratio of multicarrier transmission schemes such as OFDM is proposed. The principle of the scheme is illustrated with the specific example of a four-carrier signal. It is shown that the peak to mean envelope power ratio of this signal can be reduced from 6.02 dB to 2.48 dB with a 3/4 rate block code. The application of the block coding principle with flexibility such that the coding rate can be traded against peak to mean envelope power ratio is illustrated with the example of an eight-carrier signal.
18177627
PAPR reduction in OFDM system using adapting coding technique with pre distortion method
In this paper we propose the Peak to Average Power ratio reduction (PAPR) in OFDM using adapting coding technique with pre-distortion method to decrease the nonlinear distortion and to improve the power efficiency of the non-linear high power amplifier (HPA). In the proposed method adaptive coding is used for error correction as well as PAPR reduction. The pre-distorter improves the bit error rate performance of the system.
28267069
Companding transform for reduction in peak-to-average power ratio of OFDM signals
A general companding transform method is proposed to effectively reduce peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals. By compressing large signals while enhancing small signals along with taking into account their statistical characteristics, this method can achieve significant reduction in PAPR with low implementation complexity. Specifically, we present the design criteria of the transform, which enable effective tradeoff between reduction in PAPR and bit-error rate performance of the OFDM system. It is shown by simulations that the proposed method may significantly improve the performance of OFDM systems in radio channels by carefully choosing the companding form and parameters.
8843220
A Modified Selected Mapping Technique to Reduce the Peak-to-Average Power Ratio of OFDM Signal
In this paper, we propose a modified selected mapping technique to reduce the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) system. In this technique, we choose a vector with low PAPR in each coset of a linear block codes as its coset leader, instead of the weight vector in conventional technique. And a sequence which is most likely to yield the lowest PAPR is chosen to transmit before IFFT by a decision algorithm. Simulation results show that the modified technique has good performance in PAPR reduction.
5569739
Tone Reservation Using Near-Optimal Peak Reduction Tone Set Selection Algorithm for PAPR Reduction in OFDM Systems
This letter considers selection of the optimal peak reduction tone (PRT) set for the tone reservation (TR) scheme to reduce the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) signal. In the TR scheme, PAPR reduction performance achieved by a randomly generated PRT set is superior to that by a consecutive PRT set and that achieved by an interleaved tone set. However, the optimal PRT set requires an exhaustive search of all combinations of possible PRT sets, which is known to be a nondeterministic polynomial-time (NP)-hard and cannot be solved for the practical number of tones. Inspired by the efficiency of the cross-entropy (CE) method for finding near-optimal solutions in huge search spaces, this letter proposes the application of the CE method to search the optimal PRT set. Computer simulation results show that the proposed CE method obtains near-optimal PRT sets and provides better PAPR performance.
60474737
Peak-to-average power ratio reduction of an OFDM signal using partial transmit sequences
Orthogonal frequency division multiplexing (OFDM) is an attractive technique for achieving high-bit-rate wireless data transmission. However, the potentially large peak-to-average power ratio (PAP) of a multicarrier signal has limited its application. Two promising techniques for improving the statistics of the PAP of an OFDM signal have previously been proposed: the selective mapping and partial transmit sequence approaches. Here, we summarize these techniques and present suboptimal strategies for combining partial transmit sequences that achieve similar performance but with reduced complexity.
44256293
Peak-to-average power ratio reduction in orthogonal frequency division multiplexing system using differential evolution-based partial transmit sequences scheme
A differential evolution (DE)-based partial transmit sequence (PTS) scheme for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems has been proposed. PTS techniques can improve the PAPR statistics of an OFDM signals, but the considerable computational complexity for the required search through a high-dimensional vector space is a potential problem for the implementation in practical systems. The DE is an efficient and powerful population-based stochastic search technique for solving optimisation problems over continuous space, which has been widely applied in many scientific and engineering fields. Thus, to reduce the complexity for searching phase weight vector and to improve the PAPR statistics, the authors introduce DE, to search the optimal phase weight factors. The simulation results show that the proposed DE-based PTS obtains an excellent PAPR performance with a low computational complexity.
21796789
Partial Transmit Sequences for PAPR Reduction Using Parallel Tabu Search Algorithm in OFDM Systems
In this letter, partial transmit sequences (PTS) based on parallel tabu search (Parallel TS-PTS) scheme is proposed to reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals. PTS is a distortionless PAPR reduction technique, but its high search complexity for finding optimal phase factors must be reduced for usable applications. Parallel TS-PTS is compared to different PTS schemes for PAPR reduction and search complexity performances. The simulation results show that the proposed parallel TS-PTS method provides good PAPR reduction and bit-error-rate (BER) performances.
6293926
PAPR reduction of OFDM signals using harmony search algorithm
Orthogonal frequency division multiplexing (OFDM) is one of the widely used multiplexing techniques in wireless communications and especially cognitive radio networks. One of the key challenges of this technique is its high peak to average power ratio (PAPR) of the transmitted signal. This paper, introduces a new approach to PAPR reduction of OFDM signals using harmony search algorithm (HSA) based on the partial transmit sequence (PTS) method. The simulation results demonstrate that the proposed algorithm has better PAPR reduction performance as an accurate and low complexity approach for OFDM systems.
35118759
Improved particle swarm optimization for PAPR reduction of OFDM systems
PTS is highly efficient in peak-to-average power ratio (PAPR) reduction of OFDM systems, but the considerable computational complexity for the required search through a high-dimensional vector space is potential problem for a practical implementation. In this paper, we formulate the search problem of PTS as a combinatorial optimization (CO) problem, then propose an algorithm based on improved discrete particle swarm optimization (I-DPSO), which reduces the number of multiplications required for PTS. Numerical results show that, the proposed algorithm can achieve performance-complexity tradeoff for moderate PAPR reduction.
58908445
Review and Comparison of BAT and PSO MPPT’s Based Algorithms for Photovoltaic System
Optimization can be defined as an effort of generating solutions to a problem under constrained 
circumstances utilizing the existing resources with the finest way. Literature proposes many variants of optimization 
methods inspired from nature such as evolutionary algorithms and swarms intelligence algorithms. Swarm 
intelligence is considered as a powerful method suitable for optimization problems. For instance, Bat algorithm has 
been inspired by bats behavior during their flight and hunting. Particle Swarm Optimization algorithm has been 
inspired by social behavior of fish schooling or bird flocking 
In this work, an attempt is made to validate experimentally and analyses the performance of Bat and PSO algorithm. 
A standard test has been carried to evaluate the ability to track the global maximum point of the photovoltaic panel 
under a step change in irradiance Furthermore under partial shading conditions. The main equations that govern the 
behavior of each algorithm are also explained. Furthermore, this paper outlines how far BA algorithm outperforms 
PSO with respect to the tracking capability, transient behavior, and convergence criteria as results of his excellent 
features. It is envisaged that the BA algorithm can be suitably used as an MPPT technique, particularly for large PV 
array under various weather condition.