TABLE OF CONTENTS The services that CDMA can provide include voice services, medium rate data services, messaging services, and location based services.
Voice service is a type of communication service where two or more people can transfer information in the voice frequency band (not necessarily voice signals) through a communication network.
The IS-95 CDMA system provides for digital and analog voice service. Analog voice service is performed by frequency modulation (FM). Digitizing and compressing a digitized audio signal perform a digital voice service.
The voice service quality on the IS-95 CDMA system can vary based on a variety of factors. The CDMA system can dynamically change the voice quality Variable voice quality. This is because the CDMA system can use various types of speech compression and the service provider can select and control which speech compression process (voice coding) is used. The selection of voice coders that have higher levels of speech compression (higher compression results in less digital bits transmitted) allows the service provider to increase the number of customers it can provide service to with the tradeoff of lower quality audio signals.
Data Services are communication services that transfer information between two or more devices. Data services may be provided in or outside the audio frequency band through a communication network.
When data signals are transmitted in the audio band (below 4 kHz), a data modem must be used on an analog radio channel. The data modem converts the data signal (digital bits) into tones that can...
