| Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation scheme utilized as a modulation method in high speed wireless and mobile communications systems such as digital subscriber lines, wireless LANs, digital video broadcasting, WiMAX and other emerging wireless broadband systems, including LTE. However, one major drawback of OFDM is its inherently high peak-to-average power ratio (PAPR), which can cause severe nonlinear distortion when a nonlinear high power amplifier (HPA) is used. High PAPR is one of the most important implementation challenges in OFDM schemes, because it reduces the efficiency and hence increases the cost of the radio frequency (RF) power amplifier, which is one of the most expensive components in a radio. This dissertation proposes a novel approach to minimize the impact of PAPR. Most current PAPR reduction techniques aim to minimize PAPR in the transmitter; the work presented here studies PAPR reduction techniques in the receiver and their effects on the performance of OFDM systems. Extensive analysis was performed to compare the performance gain of each reduction technique. The results obtained in different channels such as SISO and MIMO show that the new peak restoration technique achieves a four-fold performance improvement on average in the SISO channel, and it can support other previously published approaches as well. |
