Par reduction in the uplink for OFDMA systems

Orthogonal frequency-division multiple access (OFDMA) technology is being considered for uplink (UL) transmission in future mobile standards. While such systems can enjoy the advantages of OFDM, it also shares its disadvantages, and in particular, a large peak-to-average power ratio (PAR). PAR reduction techniques can be employed, but with a fraction of the bandwidth used by each user, the UL-OFDMA scenario is different than for traditional OFDM systems. Tone reservation has been proposed as one technique in recent 3GPP standards meetings, but in this paper, we offer more efficient algorithms that are well-suited for the UL-OFDMA case and easily incorporate any necessary power-spectral density (PSD) constraints.