hat additional spectrum is being Interfering Signal proposed to supplement what is already designated for unlicensed use in the 5 GHz band. Increased access We have grown to expect near-ubiquitous coverage from Figure 1.0-6 Smart antenna. In this simple example, the desired and interfering signals are captured at each antenna element. our cellular phone carriers. This has been achieved When aligning the received signals to maximize the desired signal, through network tuning and intensive investment in the offset versions of the interferer tend to cancel each other out. network infrastructure. Next generation technology and Introduction CHAPTER 1.0 Growth of Mobile Network Access Devices Other Potential Network Access Devices Mobile Phones Figure 1.0-7 Growth of mobile network access devices [9]. "Other" devices include PDAs, handheld and laptop PCs, etc. business consolidations should provide even more in- Platform, Micro Edition [J2ME], binary runtime ternational roaming capabilities. Where there are several environment for wireless [BREW], extensible noninteroperable cellular technologies today, there are markup language [XML]), and video compression only two contenders for widespread international de- algorithms, also have the end result of ployment in the third generation, and cellular operators providing more capability-and more are ensuring a much greater degree of compatibility be- configurable capabilities-to our mobile devices. tween them. Additionally, the burgeoning growth of We are now seeing not only wireless phones and laptop public and private Wi-Fi hot spots offers mobile data computers, but also radio-connected PDAs, cameras, users another connectivity option. Bluetooth users carry watches, and cars. Any device that has an embedded their own PAN around with them wherever they go. microprocessor is a candidate for wireless connectivity. And it is expected that satellite services will provide Figure 1.0-7 illustrates the growth in mobile network increasing connectivity options for those hard-to-rea