Technical Challenges of Wireless Communications

This chapter describes the basic technical challenges for wireless communications systems, and discusses the difference to the challenges encountered in wired communications. The first big challenge is multipath propagation, i.e., the existence of multiple signal copies arriving at the receiver. Multipath propagation in turn leads to fading and intersymbol interference. A further challenge is the limited amount of spectrum available for wireless communications; the chapter briefly discusses the most important frequency bands assigned to various wireless services, and the difference between regulated and unregulated spectrum. A brief discussion of the challenges of limited energy available at mobile stations, and of the impact of mobility, concludes the chapter.