A Study on PAPR Reduction in OFDM Wireless Systems

Orthogonal Frequency Division Multiplexing (OFDM) has well known advantages such as robustness against frequency selective fading and narrowband interference, high efficiency on bandwidth, and efficient implementation. Recently, OFDM has been widely used in digital audio broadcasting (DAB), digital video broadcasting-terrestrial (DVB-T), mobile multimedia access communication (MMAC), IEEE802.11a/g/n, IEEE802.16 and IEEE 802.20. A major drawback of OFDM is a large peak to average power ratio (PAPR) which causes a nonlinear distortion. Owing to a large PAPR, the bit error rate (BER) performance of an OFDM system becomes degraded. Several techniques to reduce PAPR have been proposed. These techniques are known as amplitude clipping and filtering, peak cancellation, coding, interleaving, selective mapping (SLM), tone reservation (TR) and tone injection (TI), active constellation extension (ACE), partial transmit sequence (PTS) approach and cascade adaptive peak power reduction (CAPPR) approach. Among these conventional methods, PTS and CAPPR have been considered as high efficient PAPR reduction methods. However, it is difficult to get large PAPR reduction only by using PTS. On the other hand, CAPPR cannot suppress out-of-band radiation where PTS realizes lower out-of-band radiation than CAPPR. This thesis proposes a new PAPR reduction technique. This technique employs the hybrid of PTS and CAPPR methods with coded side information (SI) technique. A