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We consider improving the performance of orthogonal frequency-division multiplexing (OFDM)-based mobile broadband wireless communication (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 the commonly suggested differential modulation/detection methods
broadband networks, channel coding, convolutional codes, decoding, mobile radio, OFDM modulation, packet radio networks, polynomials, signal detection, signal processing, time-varying channels,packet design, signal processing, OFDM, mobile broadband wireless communication systems, orthogonal frequency-division multiplexing, time-varying channels, convolutional channel encoder, signal detection, decoding, channel response, subpacket, weighted polynomial fitting,Process design, Signal design, Signal processing, Broadband communication, Wireless communication, Time-varying channels, Frequency division multiplexing, Degradation, Tail, Convolution,Dedicated Short Range Communications (DSRC), Mobile Broadband Wireless Access (MBWA), broadband wireless access (WiMax), WLAN (Wi-Fi), OFDM, subpacket, channel estimation, polynomial fitting.
"Packet Design and Signal Processing for OFDM-Based Mobile Broadband Wireless Communication Systems", IEEE Transactions on Mobile Computing, vol. 5, no. , pp. 1133-1142, September 2006, doi:10.1109/TMC.2006.136
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