Research On PAPR In Next Generation Of WLAN

With the rapid development of modern science and information industries, people constantly increase the needs of communication quality.Existing spectrum source of communication system, the transmission rate and system capacity can not meet the growing communication needs. Communication technology with high speed and large capacity catches more and more people’s attention.WLAN (Wireless Local Area Network), because of its high throughput, low cost, It has become an indispensable means of information transmission in the Internet era. WLAN provide users with high-speed wireless Internet service, its standard always pursue the development of high throughput and large bandwidth. In the development process of WLAN, standard using new technical to increase the data transfer rate. OFDMA (Orthogonal Frequency Division Multiple Access) technology has higher data transfer rates and bandwidth efficiency,so it has gradually become the mainstream technology of WLAN. Since OFDMA technique is used multi-carrier to transmission signal, so there is a certain probability of the system, the higher peak signal appears. A peak value of the signal will result in the existence of WLAN system Peak to Average Power Ratio. If the higher peak signal to work within the linear range of the amplifier system, it is bound to increase the cost of WLAN systems. So Inhibition Peak to Average Power Ratio is very necessary.In a WLAN system, PAPR(Peak to Average Power Ratio) suppression algorithm can be summarized into three categories:the signal pre-distortion algorithm, coding algorithm and probability classes algorithm. In order to study PAPR suppression algorithm, Firstly, analysising the characteristics of each method in theoretical, using Matlab software to simulation. Because the signal distortion caused by the pre-distortion algorithm, encoding algorithm is not available for the large number of subcarriers systems, the paper ultimately select PTS (Partial Transmit Sequence) algorithm to depth study. Then, we Observed PTS algorithm performance in three aspects:the sub-blocks mode, the phase of the number of factors, the number of sub-blocks. Analysising PTS algorithm in theoretical and using simulation Verify the theoretical. Finally, based on the conclusion,PTS algorithm performance is related to the alternative signal. It proposes a cycle shift in time domain to increase the alternative signal. The Improved algorithm has lower computational complexity, compared to the PTS algorithm, The Improved algorithm has better performance.