Studies of Peak-to-Average Power Ratio Reduction for OFDM Signals

• Main Authors: Tung, Yuan-Hao, 董原豪
• Other Authors: Su, Yu-Ted
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/89647820959131044676

碩士 === 國立交通大學 === 電信工程研究所 === 98 === In this thesis we propose several approaches for reducing peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals. The conventional clipping approach clips the magnitude of a time-domain OFDM waveform while leaving its phase intact. We present a novel time-domain clipping method with hybrid frequency domain constraint by independently clipping both real and imaginary parts of a complex time-domain OFDM waveform and using linear pro- gramming (LP) to obtain the optimal clipped signal. Selective mapping (SLM) often requires that side information about the mapping sequence used be sent along with the desired data sequence. Maximum likelihood de- tection without side information is realized at the cost of much higher complexity. We proposed a novel SLM sequences design which enable a receiver to use a simple detector without side information, leading to bandwidth e±ciency and capacity improvement. The proposed design also has the advantages of simple encoding implementation and low memory requirement. When SLM side information is needed for signal detection, it is often protected with a low rate forward error-correcting code. We propose an SLM scheme with embedded side information. Active constellation extension (ACE) and projection onto convex set (POCS) techniques are used to adjust side information for both reducing PAPR and achieving better SLM index detection probability.