Services
Date: 2015-10-07; view: 409.
Part IV (47.6 – 47.8)
The primary purpose ofall cellular radio networks is to offer speech telephony service to its customers. In addition most networks offer a range of supplementary and value added services to enhance the basic product.
In analogue systems, basic telephony is provided directly by the audio path between mobile and network. Other than some linear speech processing to increase the channel's signal to noise performance, the audio path is transparent across the speech band, allowing other sounds (tones, non-voice signals etc) to pass through undistorted. By contrast GSM (and other digital systems) use a speech coder tailored to voice characteristics. They therefore provide a fully acceptable telephony service, but non-voice signals can suffer distortion across the non-audio transparent path.
Figure 47.14Location updating
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