Phase modeling of indoor radio propagation channels

Two models for generating phase of individual multipath components in an in door environment, partly developed in II], have been studied in detail. In the deterministic phase increment model (model I), phase of each multipath component is updated deterministically using several independent random sca tterers. In the random phase increment model (model II), phase of each mult ipath component is updated by adding independent random phase increments, P erformance of these models has been evaluated by means of extensive compute r simulations. Statistical properties of narrow-band CW fading signals obta ined using each phase model have been compared with the corresponding resul ts for a large empirical wide-band database of 12 000 impulse response esti mates of indoor radio propagation channels. A major conclusion is that mode l I (with five scatterers for each multipath component) and model II (with proper choice for phase increments) provide fading results consistent with those obtained from measurements. In this paper, properties of each phase model are described, and an algorit hm for generating each is presented. First- and second-order statistics [am plitude distributions, level crossing rates (LCR's), and average duration o f fades (ADF's)] and Doppler spectra of narrow-band CW fading waveforms obt ained using simulated phases are reported, and detailed comparison between the simulated and empirical results is carried out. Furthermore, the two mo dels are also compared with each other, and advantages and disadvantages of each are explored. The effect of increasing the number of scatterers and s tatistical properties of phase increments in model I are studied, simulated , and compared with model II, A major conclusion is that for an appropriate choice of parameters, both models provide satisfactory performance, Comput ation time of model I is, however, on the average 1.7 times of model III ma king it less efficient for generating a large number of impulse response pr ofiles, The results reported in this paper can be used in performance evaluation of wireless indoor communication systems, either directly or by developing a comprehensive channel simulator.