Low PAPR Subchannelization Preamble Design for Uplink Transmission in IEEE802.16 2004 OFDM PHY System

Orthogonal frequency division multiplexing (OFDM) is a key enabling technology for future wireless communications systems. OFDM makes equalization simple and effective. However, accurate channel estimates are of paramount importance at the receiver for the operation of OFDM systems. Channel estimation usually employs some form of training signal, also known as the preamble, in the front of the packet. It is desirable to have a preamble signal with the lowest peak-to-average power ratio (PAPR) so that the estimation signal to noise ratio (SNR) can be maximized.
In this work, we address the problem of designing low peak-to-average power ratio (PAPR) subchannelization preamble for uplink transmission in IEEE802.16 2004 orthogonal frequency division multiplexing (OFDM) system. The initial preamble is designed using generalized chirp like (GCL) sequences. In order to obtain the lowest PAPR, the preamble is optimized using constrained nonlinear optimization technique. Results obtained show that the proposed subchanneliztion preambles have PAPR as low as 1.7902 dB and exhibit gains up to 2.3038dB when compared to the prescribed subchannelization preamble of IEEE 802.16 2004 standard.