چكيده به لاتين
Employing multi-carrier modulation technique in wireless channels not only resolves the phenomenon of feeding caused by multipath channel but also enhances the rate of data transmission in these channels. Known as the most common multi-carrier modulation, OFDM is associated with strengths and weaknesses. Presence of high peaks in the time domain signal is one of the major weaknesses, which causes distortions and an increase in bit error rate and reduces the efficiency of the system due to existence of amplifiers and digital-to-analog converters. Therefore, it is necessary to employ a method that can reduce Peak-to-Average Power Ratio (PAPR). SLM and PTS are among efficient methods to reduce PAPR.
we first derive this condition which we call the ITSM (identically-time-shifted multicarrier) condition. Then, based on this condition, we propose a new type of FBMC for low PAPR.
The main features of the proposed scheme are summarized as follows. Firstly, in order to further enhance the amount of PAPR reduction, we generate the four candidate versions of
the DFT-spread and ITSM-conditioned FBMC waveform and select the one with minimum peak power.
In SLM method, a change in the phase of each subcarrier available in input-data block, new signals with different PAPR from the main signal are produced. By comparing the amount of PAPR of the main signal with its changed-phase versions, a signal with minimum amount of PAPR will be selected to be sent. SLM has a high level of precision and efficiency in reducing PAPR; however, it imposes a lot of calculation complexities on the system.
The procedure in PTS is like the one in SLM with this difference that in PTS the input-data block is divided into equal smaller sub-blocks, and all subcarriers available in the sub-blocks are phase-changed using an equal phase. PTS method not only reduces the amount of PAPR but also imposes less calculation load on the system.
In this paper, an effective PAPR reduction scheme has been proposed. The proposed method is a combination of LOW PAPR FBMC,SLM and PTS . In this method first generate a FBMC waveform which has low PAPR and then apply the other two methods on It . As the results of simulation indicated, the proposed method has a low PAPR compare with Kwonhue and Dongjun methed , but it has more complexity .
