Design and Implementation of Spectrally Precoded OFDM Transceiver based on IEEE 802.16m

在本論文中，我們針對前人所提出的頻譜預編碼正交分頻多工系統設計並實作適用於IEEE 802.16m之收發機。 正交分頻多工系統在抗多路徑衰減通道中擁有優異性能，因而被廣泛應用於無線通信網路中，但是其功率頻譜密度中，旁葉的下降不夠快速，導致不同頻率使用者間造成互相干擾，一般解決方法是不用邊緣子載波來傳輸資料並加上類比低通濾波器來降低頻譜外功率，但這樣子降低了傳輸效率，也增加了系統複雜度。 預編碼正交分頻多工系統可以有效壓制頻譜外功率，但是在實際系統上還有許多待解決的課題，本篇論文針對IEEE 802.16m之規格，以及實際系統所會應用到的技術，設計出適用於IEEE 802.16m的預編碼正交分頻多工系統，並著重於通道估計部分，其位元錯誤率在某些條件下接近甚至優於無預編碼之系統。In this thesis, we proposed the design and implementation spectrally precoded orthogonal frequency division multiplexing (SP-OFDM) based on IEEE 802.16m. Orthogonal frequency division multiplexing (OFDM) system is known for its ability against multipath fading channel. Therefore, OFDM system is widely used in wireless communication system. But in the power spectrum density of OFDM, the sidelobes decaying is not fast enough so the interference between users in different frequency occurs. The general solution is setting null subcarriers in the border of bandwidth and using the analogue low pass filter to suppress the out-of-band power. This method decreases the transmission rate and increases the complexity. SP-OFDM is good to suppress out-of-band power but still have a lot of topics to research. This thesis considers the implement technique in the OFDM and design the SP-OFDM based on IEEE 802.16m standard, and concentrate on the channel estimation. The performance of average bit error rate (BER) is similar and even better than nonprecoded OFDM under certain scenario