Abstract:Multi-user interference occurs in an asynchronous time hopping impulse radio ultra-wide band (IR-UWB) multi-user system, therefore the asymptotic bandwidths of IR-UWB signal of dense network and extended network are derived respectively when the multi-user interference can be negligible with respect to output noise with high probability. The theoretic study results indicate that the obtained asymptotic bandwidth of IR-UWB signal is in direct proportion to the numbers of user. The asymptotic bandwidth of IR-UWB signal required by the dense network is much more than that by extended network. As the bandwidth of IR-UWB signal satisfies the obtained theoretic asymptotic bandwidth, the probability of error of the multi-user system is simplified to that of the single user system.