Ofdm All-digital Receiver Design

At present, Orthogonal Frequency Division Multiplexing (OFDM) technique has been widely used in wideband wireless communication systems, such as DVB and IEEE 802. lla, because of its various advantages in lessening the severe effects of ISI. Based on the WLAN standard IEEE 802. lla, this thesis focus on design and study of all-digital demodulation algorithms in OFDM receivers, including frame synchronization, frequency estimation , channel estimation and implemention of the OFDM demodulation.Frame synchronization is of most importance in a OFDM translating system. Normally, we search the Frame synchronization through computing the peak of self-correlation. Because of frequency offset, the peak of self-correlation maybe vanishes. First, this thesis presents a solution trough compute the peak of auto-correlation basing on the STANDARD 802. 11a framing structure.Secondly, we analyze the frequency estimation algorithm in IEEE 802. lla standard. Both coarse frequency estimation and fine frequency estimation will be used in this OFDM digital receiver to wide the capturing range and to improve the capturing precision. Further,this thesis investigates the channel estimation scheme for IEEE 802. lla to improve the system performance in time-variant channels.Finally,we present the Implementation of the OFDM digital receiver with TMS320C6701 and Xilinx' s FPGA.DSP and FPGA resolution is prefered because of its flexibility and software intelligenzation. And in this last chapter, we also represent the solution to the problem in the process of hardware design.