OFDM 시스템에서 PAPR 감소를 위한 PTS 기법의 성능개선에 관한 연구

Abstract

Nowadays, there has been a need for high-speed and high-quality services including voice, image, and other various multimedia signals applied to wireless communication systems. It is well-known that OFDM system has better characteristics in transmission rate, power efficiency, bandwidth efficiency, impulse-noise immunity, and narrow band interference immunity etc. in comparison with other conventional systems.

However, various interferences between sub-channels and higher PAPR can easily occur when data is transmitted via parallel sub-carriers. High PAPR causes some serious non-linear processing of RF amplifier. And performance of the communication system gets worse.

Therefore, various methods reducing PAPR of OFDM skills such as the clipping method, block coding method, and phase rotation method etc. have been researched. However, these methods cause in-band interference and degrade the signal quality. Moreover, the amount of calculation is exponentially increased according to the number of sub-carriers and additional error with time-delay can occur because of side information. As a result of these defects, it is difficult to apply these conventional methods to real-time high-speed transmission systems.

In this paper, we propose a high-speed adaptive PTS method which eliminates high PAPR. And we compare the proposed method with other conventional methods. Using the computer simulation program, the proposed method has decreased quantity of calculation compare with the adaptive PTS method. Of course, The more its calculation amount is decreased, the more its BER characteristic is not better than the adaptive PTS method. This means a calculation amount and BER characteristic is trade offs. However, keeping up satisfactory BER performance, we highly improved calculation amount of PTS method. Based on the results of computer simulation, It is expected that the proposed method can be used in the high-speed transmission systems.