On the performance of UWB and DS-spread spectrum communication systems

We consider a binary spread spectrum system, with possibly episodic transmission; i.e., the system transmits n pulses per information bit, and allows for off time separation between pulses. Processing gain enables low power transmission, and the ultra wideband (UWB) spreading limits the interference effects into narrowband systems. We consider the issues of processing gain, jamming margin, coding gain and multiuser interference (MUI) for a single user matched filter receiver. The introduction of episodic transmission, with a corresponding reduction in bit rate, provides system flexibility with respect to both MUI rejection and handling of multipath channels. Highly episodic transmission provides nearly orthogonal users, even with system asynchrony and no power control. Performance of a single user matched filter in the presence of MUI is given via a Chernoff bound on bit error rate.