Title :
A study of non-uniform pilot spacing for PSAM
Author :
Lo, Herman ; Lee, Diane ; Gansman, Jerome A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Maryland Univ., College Park, MD, USA
Abstract :
Pilot symbol assisted modulation (PSAM) achieves coherent demodulation in a fading environment by inserting known symbols into the data stream. The receiver uses these pilot symbols to estimate its amplitude and phase reference. Although the pilots are typically spaced uniformly, adding extra consecutive pilot symbols allows one to estimate a large frequency offset on the channel. This work uses computer simulations to investigate the bit error probability (BEP) of PSAM with various non-uniform frame structures. It is shown that for higher Doppler rates, a non-uniform frame structure yields a lower BEP than a comparable uniform frame. Furthermore, in the presence of an unknown frequency offset, a non-uniform frame performs much better because it can estimate and remove the frequency offset prior to compensating for the fading process
Keywords :
Doppler effect; amplitude estimation; demodulation; digital simulation; error statistics; fading channels; frequency estimation; quadrature amplitude modulation; Doppler rates; Gray coded 16QAM data; PSAM; amplitude reference estimation; bit error probability; coherent demodulation; computer simulations; data stream; fading compensation; fading environment; frequency offset; nonuniform frame structures; nonuniform pilot spacing; phase reference estimation; pilot symbol assisted modulation; pilot symbols; receiver; Antenna arrays; Antennas and propagation; Delay estimation; Directive antennas; Fading; Low pass filters; Quadrature amplitude modulation; Sampling methods; Throughput; Wiener filter;
Conference_Titel :
Communications, 2000. ICC 2000. 2000 IEEE International Conference on
Conference_Location :
New Orleans, LA
Print_ISBN :
0-7803-6283-7
DOI :
10.1109/ICC.2000.853168