Question

Difference between half rate and full rate in gsm

Answer 1

 GSM-FR was the first digital speech coding standard used in the GSMdigital mobile phone system. The bit rate of the codec is 13 kbit/s, or 1.625 bits/audio sample (often padded out to 33 bytes/20 ms or 13.2 kbit/s). The quality of the coded speech is quite poor by modern standards, but at the time of development it was a good compromise between computational complexity and quality, requiring only on the order of a million additions and multiplications per second. The codec is still widely used in networks around the world. Gradually FR will be replaced by Enhanced Full Rate  and Adaptive Multi Rate standards, which provide much higher speech quality with lower bit rate.