ABSTRACT
Wireless radio communications are based on transmission of radio waves through the air. Modulation techniques embed a signal into the carrier frequency. They can be classified into analog and digital modulations. Two basic wireless system topologies are point-to-point and networked topology. Code division multiple access is a radically different air interface technology that uses the frequency-hopping spread-spectrum technique. The IEEE 802.20 standard is a broadband wireless networking technology that is being standardized for deployment by mobile communications service providers, in portions of their licensed spectrum. Wi-Fi, which stands for “wireless fidelity,” is a radio technology that networks computers so they connect to each other and to the Internet without wires. The new wireless platform, Microwave Access holds promise of high-speed Internet delivered to handheld devices. It delivers higher speeds than Wi-Fi over a much longer distance. The first generation of wireless systems was introduced in the late 1970s and early 1980s, and was built for voice transmission only.
