3G Handset and Network Design

CHAPTER 13

Network Hardware Optimization

In this chapter we review some radio hardware optimization opportunities and their impact on radio bandwidth quality, as well as optical hardware optimization opportunities and their impact on network bandwidth quality). But, first, we need to go back to school and review some basic concepts.

A Primer on Antennas

Figure 13.1 reminds us of how a radio wave travels through free space with an electric field component and a magnetic field component. The distance from trough to trough is the wavelength; the number of waves passing in Hz (cycles per second) is the frequency. Antennas are used to transmit or receive these waves. Antennas are passive components dimensioned to resonate at a particular frequency or band of frequencies.

In Chapter 1 we showed how wavelength decreases with frequency (see Table 1.1). We normally design handset and base station antennas to resonate at fractions of a wavelength. Antennas therefore become more compact as frequency increases, but they also become less efficient and more subject to localized effects such as coupling between antennas on a mast or between antennas and the mast or (in handsets) capacitive coupling effects (the effect of our hand on the outside of the phone).

On handsets, fashion now determines either internal antennas or external stub antennas, which may or may not be 1/4 wave or 1/8 wave. These are inefficient lossy devices. A number of companies have developed proprietary techniques for improving ...