Title :
Error floors in narrowband digital FM systems
Author :
Petrovic, Rade ; Filipovic, Srdan
Author_Institution :
Center for Wireless Commun., Mississippi Univ., University, MS, USA
Abstract :
A digital FM system in the presence of simulcast interference and/or Rayleigh fading exhibits performance floors, where increased signal strength does not reduce the error rate. The mechanism which generates FM clicks even in the region of high SNRs, in simulcast as well as in multipath, is suggested. It is shown that a simple model based on two unmodulated carriers is capable of not only qualitatively explaining the phenomenon, but also of providing quantitative estimates which match well with experimental results obtained both in laboratory and in field tests. The observed “equivalency” of the Doppler spread and the frequency offset in their effect on the BER has been given an analytic form. The analysis applies to a narrowband M-FSK system with FM discriminator and post-detection filter
Keywords :
Doppler effect; Rayleigh channels; coding errors; digital radio; discriminators; error statistics; fading; filtering theory; frequency modulation; frequency shift keying; land mobile radio; multipath channels; personal communication networks; radiofrequency interference; 940 MHz; BER; Doppler spread; FM clicks; FM discriminator; PCS channel; Rayleigh fading; UHF; digital FM system; error floors; error rate; experimental results; field tests; frequency offset; high SNR; laboratory tests; multipath; narrowband M-FSK system; narrowband digital FM systems; performance floors; post-detection filter; quantitative estimates; signal strength; simulcast interference; unmodulated carriers; Amplitude modulation; Bit error rate; Detectors; Fading; Frequency modulation; Interference; Narrowband; Oscilloscopes; Phase noise; Transmitters;
Conference_Titel :
Southeastcon '97. Engineering new New Century., Proceedings. IEEE
Conference_Location :
Blacksburg, VA
Print_ISBN :
0-7803-3844-8
DOI :
10.1109/SECON.1997.598681
