Performance Evaluation of Time Hopping UWB ... - Ripublication.com

548 Athar Ravish Khan and Sanjay M. Gulhanestandard deviation of the fluctuation of the channel coefficient for pulse within a theclusters, σ g , is standard deviation of the channel amplitude gain.Table 2 Parameter for environmental characteristics of Underground MineModified UWB Channel forUnderground MineΛ λ Г γ(1/ns) (1/ns)0.0667 2.1 36 24σ ξ (dB) σ ζ (dB) σ g (dB) Type3.3941 3.3941 3 LOSThe mean excess delay and RMS delay spread are two important parameters useto characterize the temporal dispersive properties of the multipath channel. The RMSdelay spread parameter determines the frequency selectively of the channel whichdegrades the performance of digital communication systems. The RMS delay spreadlimits the maximum data transmission rate that can be reliably supported by thechannel figure (5) shows the RMS delay of Underground Mine Channel and figure (6)shows the Excess delay of Underground Mine Channel, simulated for 100 number ofchannel. The clustering of the multipath arrivals is evidence observed in figure (3),this validates the multi-paths arriving in clusters of UWB channel measurement data.It is the typical result in the multipath attenuation channel, any more the amplitudefading statistics of the channel impulse response are exponential. It can be seen thatbefore 300ns the amplitude fading lentamente, here the model is able to best fit thechannel propagation law, but after 300ns, the amplitude fading prick up and almostnear zero.Discrete Time Mine Channel Impulse Response10.80.60.4Amplitude G ain0.20-0.2-0.4-0.6-0.8-10 100 200 300 400Time [ns]Figure 3 Discrete time impulse response of Underground Mine Channel.