Minimization of PAPR in MIMO-OFDM Systems by Tone Reservation Techniques and Pilot Tones

In this paper a method that mixes tone reservation (TR) techniques and phase information of the pilot tones to efficiently reduce the peak to average power ratio (PAPR) of the multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) signals is presented. First, we utilize convex optimization techniques to design dummy symbols to unused or reserved set of subcarriers to reduce the PAPR of the transmitted data in an OFDM symbol. Then, to the pilot tones dedicated for channel estimation, we design phase information to further reduce the PAPR. To design phase information of the pilot tones in MIMO-OFDM systems, we resort to the previously proposed cross entropy (CE) optimization techniques used for pilot phase design in single input single output (SISO) OFDM systems. Simulation results show that, by mixing the dummy symbols and pilot phase information the PAPR of the MIMOOFDM signals can be effectively reduced.