Title :
A New Defined Lower Bit Rate AMR Mode in GSM and WCDMA Networks
Author :
Guo, Yi-Feng ; Kuo, Geng-Sheng G S
Author_Institution :
Nat. Key Lab. of Networking & Switching, Beijing Univ. of Posts & Telecommun.
Abstract :
Adaptive multi-rate (AMR) codec can adaptively select one of eight modes according to the channel condition or the system load. AMR allows making a trade-off between voice capacity and the voice quality. In GSM networks, when the channel condition is worse than the threshold, the voice quality is unacceptable even using the lowest rate mode (4.75 kbps). In this paper, by compressing the AMR frame, a new defined lower bit rate AMR mode with 3.95 kbps is proposed to guarantee the voice quality in this case. The proposed mode is completely compatible with the specified AMR codec in standard. Moreover, this mode can be adopted in WCDMA networks. Compared with 12.2 kbps mode, this new one can increase the capacity by 135% and increase the coverage gain by 2.6 dB.
Keywords :
cellular radio; code division multiple access; AMR mode; GSM networks; WCDMA networks; adaptive multi-rate codec; voice quality; Bit rate; Code standards; Decoding; GSM; Multiaccess communication; Multiuser detection; Predictive models; Speech analysis; Speech codecs; Speech synthesis;
Conference_Titel :
Vehicular Technology Conference, 2007. VTC2007-Spring. IEEE 65th
Conference_Location :
Dublin
Print_ISBN :
1-4244-0266-2
DOI :
10.1109/VETECS.2007.159
