Hidden Pilots with Precoding for OFDMA Communiation Systems

In this paper, we propose the precoder with hidden pilots for orthogonal frequency-division multiple access (OFDMA) systems in order to enhance the transmission efficiency of the system and reduce peak-to-average power ratio (PAPR) which is the problem in OFDMA uplink. In wireless communication systems, the way to improve transmission efficiency is 1) to reduce bit error rate (BER) or 2) to increase data rate. In the proposed scheme, we design the precoder and hidden pilots in the transmitter and use them in the receiver for increasing data rate, caused by the saved transmission bandwidth thanks to the hidden pilots. In addition, we improve BER performance with the help of the frequency diversity gain caused by precoding. Also using hidden pilots, we enhance the PAPR performance by increasing the average output power of the signal.