TABLE OF CONTENTS UWB systems are currently undergoing intense development by a large number of commercial organizations worldwide. The goal is to provide a very high data rate for applications in wireless communications. In this chapter we present the current state of development in the field. The system concepts are still under a state of flux and what finally emerges may differ from what is presented here. However, most of the basic concepts should not change.
The first observation is the nature of wireless use and capability. From Chapter 5 on detection theory we noted that the output SNR of the detection matched filter is
for a constant envelope signal of amplitude A, and data rate R. Clearly, as R increases, the SNR goes down for a fixed A. To make up for the loss, A must increase accordingly, but A 2 is the signal power that cannot be increased without limit. The bottom line is that the wireless UWB applications are intended for a very short range. The terminology is called wireless personal area networks (WPANs), which operate over distances of the order of room size.
What is a UWB system? The following is the current definition:
Bandwidth contained within 3.1 to 10.6 GHz (communication sys.);
Maximum EIRP of ?41.3 dBm/MHz;
UWB BW defined by
No modulation scheme is implied.
Figure 13.1 shows the two-band allocation for UWB systems. The low band occupies 3.1 to 5.0 MHz, while the high...
