Overview

Digital cellular technology involves the combination of digital signal processing with cellular radio technology. Digital cellular radio technology was developed to allow more customers to be served by a reduced number of towers and to allow the addition of advanced features.

Some of the key technologies associated with digital radio include the access technologies used to coordinate multiple users in the network, digital signal processing, expanded cellular applications and different types of services.

Access technologies allow multiple telephones to access the wireless systems. Mobile telephones compete for the services of a wireless system, and the access technologies coordinate the access and assign a portion of the system resources. Different types of access technologies include FDMA, TDMA, CDMA, and SDMA. The core digital signal processing technologies used by digital radio systems include voice digitization, speech compression, control and data channel coding, phase modulation, radio signal amplification, and signaling control.

Technology applications that are key to 3rd generation wireless communication include variable rate speech coding, high-speed packet data, different classes of service, simultaneous multimedia services, shared transfer of calls between cell sites (soft handover), diversity reception, coordinated RF power control, and sleep modes to extend the battery life. The different classes of services include conversation, streaming, interactive, and background.

Radio Access Technology Basics

There are four basic types of cellular radio access technology: frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and spatial division multiple access (SDMA). Digital cellular systems fall into these categories,...