Description
Wireless communication has evolved so much today that it has greatly been integrated into everyone's life. From listening to music using Bluetooth headset, accessing information on the web on the move using WiFi or 3G to calling our loved ones who are on the other side of the globe and locating our position when lost, can be done using a plethora of wireless devices available today. This thesis addresses the problem of high peak-to-average power ratio (PAPR) found in orthogonal frequency division multiplexing (OFDM) modems. The reason for high PAPR in OFDM is the constructive addition of sinusoidal signals at different frequencies. High PAPR increases the dynamic range of power amplifier operation, thereby resulting in increased cost and chip area. This thesis proposes several high rate techniques to reduce PAPR. One technique extends the efficiency of the well known complementary code keying (CCK) OFDM. The second technique eliminates high PAPR by removing the periodicity which may exist between the bits fed to the OFDM transmitter. This rate-12/16 technique is compared to other techniques such as traditional OFDM and carrier-interferometry (CI) OFDM. Further, this thesis integrates the proposed rate-12/16 technique and CCK to obtain an improved rate-12/16 technique, which brings the PAPR value down to a new low. Bit error rates (BER) are obtained for each coding technique for comparison. The proposed rate-12/16 technique achieves good BER performance due to the coding gain it provides. The improved rate-12/16 outperformed all the techniques discussed in terms of PAPR.
