Analysis of the effects of time delay spread on TCM performance

摘要

We investigate the effect of time delay spread on trellis codednmodulation (TCM) in a wireless radio environment where equalization isnnot employed to mitigate the effects of frequency selective fading whennthe time delay spread is small. Using a random variable decompositionntechnique and a Gaussian approximation of the intersymbol interferencenterms, we obtain explicit bounds for the pairwise error probability ofnTCM over multipath Rayleigh fading channels characterized by variousnpower delay profiles. A method to calculate an upper bound of the bitnerror rate (BER) based on Jamali and LeNgoc (1995) bound is alsonpresented. These bounds are used to evaluate TCM performance as well asninvestigate the delay spread tolerance limit of TCM, including I-Q TCM,nover frequency selective fading channels