Single-junction solar cells are the most available in the market and the most simple in terms of the realization and fabrication comparing to the other solar devices. However, these single-junction solar cells need more development and optimization for higher conversion efficiency. In addition to the doping densities and compromises between different layers and their best thickness value, the choice of the materials is also an important factor on improving the efficiency. In this paper, an efficient single-junction solar cell model of GaAs is presented and optimized. In the first step, an initial model was simulated and then the results were processed by an algorithm code. In this work, the proposed optimization method is a genetic search algorithm implemented in Matlab receiving ATLAS data to generate an optimum output power solar cell. Other performance parameters such as photogeneration rates, external quantum efficiency (EQE), and internal quantum efficiency (EQI) are also obtained. The simulation shows that the proposed method provides significant conversion efficiency improvement of 29.7% under AM1.5G illumination. The other results were J_sc = 34.79 mA/cm², V_oc = 1 V, and fill factor (FF) = 85%.

The transceiver combination technology, of orthogonal frequency division multiplexing (OFDM) with multiple-input multiple-output (MIMO), provides a viable alternative to enhance the quality of service and simultaneously to achieve high spectral efficiency and data rate for wireless mobile communication systems. However, the high peak-to-average power ratio (PAPR) is the main concern that should be taken into consideration in the MIMO-OFDM system. Partial transmit sequences (PTSs) is a promising scheme and straightforward method, able to achieve an effective PAPR reduction performance, but it requires an exhaustive search to find the optimum phase factors, which causes high computational complexity increased with the number of subblocks. In this paper, a reduced computational complexity PTS scheme is proposed, based on a novel swarm intelligence algorithm, called fireworks algorithm (FWA). Simulation results confirmed the adequacy and the effectiveness of the proposed method which can effectively reduce the computation complexity while keeping good PAPR reduction. Moreover, it turns out from the results that the proposed PTS scheme-based FWA clearly outperforms the hottest and most important evolutionary algorithm in the literature like simulated annealing (SA), particle swarm optimization (PSO), and genetic algorithm (GA).

The combination of Multiple Input Multiple Output (MIMO) system with Orthogonal Frequency Division Multiplexing (OFDM) technology provides a powerful choice to increase channel capacity and improves the quality of service of wireless mobile communication systems. However, MIMO-OFDM systems are prone to high Peak-to-Average Power Ratio (PAPR), which leads to more interference and greatly limits the efficiency of the transmit high power amplifier (HPA). In this article, we propose a combinational approach is proposed, a PAPR reduction with memoryless digital predistortion (PRDPD) in order to combat PAPR in MIMO-OFDM, to improve HPA efficiency as well as linearity, and to mitigate in-band distortion and spectrum regrowth. The main idea of PAPR reduction is the rotation of phase independently in frequency and time domain based on Partial Transmit Sequence (PTS) and Selected Mapping (SLM) techniques with minimum complexity. This analysis is carried out based on Solid State Power Amplifiers (SSPA) of Saleh model and digital predistortion (DPD) as linearization technique. The simulation results show that the proposed scheme cannot only significantly reduce the PAPR, but also improves out-of-band radiation over other conventional techniques. Copyright © 2017 Praise Worthy Prize - All rights reserved.

The peak-to-average power ratio (PAPR) of an orthogonal frequency-division multiplexing (OFDM) signal can be substantially larger than that of a single carrier system. It is the major issue of concern in OFDM system which reduces the efficiency of the high power amplifier. As one of attractive techniques, partial transmit sequence (PTS) provides an effective solution for PAPR reduction of an OFDM signal. This paper aims to present a new algorithm based on PTS, in order to improve the performance in terms of Peak to Average Power Ratio. The simulations show that the PAPR can be reduced about 6.8dB and 0.5dB compared to the original OFDM and PTS technique successively. Our algorithm has been simulated by scalable OFDM system. The simulation and results are presented for IEEE 802.16-2004 standard.