文档介绍：IEEE TRANSACTIONS ON PUTING, VOL. 5, NO. 9, SEPTEMBER 2006 1133
Packet Design and Signal Processing
for OFDM-Based Mobile Broadband
munication Systems
Jianhua Liu, Member, IEEE, and Jian Li, Fellow, IEEE
Abstract—We consider improving the performance of orthogonal frequency-division multiplexing (OFDM)-based mobile broadband
munication (MBWC) systems. We show that a recently approved packet-based MBWC standard can cause the resulting
systems to suffer from severe performance degradations for time-varying channels due to the lack of a mechanism for tracking the
time-varying channels needed for coherent detection. We consider both packet design and signal processing to deal with time-varying
channels. For the packet design, we segment an entire packet into multiple subpackets—with each subpacket having zero tail bits to
reset the convolutional channel encoder—so that the detection/decoding result of each subpacket can be used to update the channel
response for this subpacket. For signal processing, we use weighted polynomial fitting and prediction at the receiver to improve the
channel tracking accuracy. Simulation results show that the coherent detection based on our new scheme can significantly outperform
monly suggested differential modulation/detection methods.
Index Terms—Dedicated Short munications (DSRC), Mobile Broadband Wireless Access (MBWA),