SNR Analysis of Multi-Rate IR-UWB over Frequency-Selective Channels

This paper is motivated by the need to design medium access control (MAC) protocols for impulse radio ultra-wide bandwidth (UWB) systems. Such protocols should determine how power and data rates should be allocated in order to optimize some performance measure. In order to develop a UWB MAC protocol, there is a need to gain insight on how the signal-to-noise ratio (SNR) is affected by different users transmitting with different rates and different power levels. In this paper, we obtain the SNR in a multi-rate system operating in a multi-path environment with time-hopping and/or direct-sequence spreading. We show that the SNR in a time-hopping system is highly affected by the low-rate users.