The evolution of IS-136: voice service

Author

Frankkila, T. ; Labone, S. ; Ramesh, R.

Author_Institution

Ericsson Erisoft AB, Lulea, Sweden

Volume

2

fYear

1998

fDate

18-21 May 1998

Firstpage

835

Abstract

The so-called 136+ features represent the first step in the evolution of the IS-136 standard towards an IMT-2000 system. In this article, we present the voice service of 136+. The main requirements for this service consist of improved quality for speech and non-speech signals, and for background noise and tandem conditions. Performance and implementation considerations lead to the selection of 8-PSK for the 136+ modulation. Listening tests reveal that the US1 vocoder, at 12.2 kb/s, satisfies the 136+ objectives. Furthermore, simulated performance in dispersive environments suggests that an equalizer may not be required. The use of a standard vocoder greatly simplifies the development of 136+, and the proposed scheme is expected to provide a cost-efficient service

Keywords

cellular radio; channel coding; land mobile radio; phase shift keying; speech coding; telecommunication standards; vocoders; voice communication; 12.2 kbit/s; 8-PSK; AMPS; IMT-2000 system; IS-136 standard; IS-136+ modulation; US1 vocoder; background noise; cellular radio; channel coding; dispersive environments; listening tests; non-speech signals; speech quality; speech signals; tandem conditions; voice service; Background noise; Circuits; Dispersion; Dual band; Equalizers; Speech enhancement; Standards development; Testing; Time division multiple access; Vocoders;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1998. VTC 98. 48th IEEE

Conference_Location

Ottawa, Ont.

ISSN

1090-3038

Print_ISBN

0-7803-4320-4

Type

conf

DOI

10.1109/VETEC.1998.683699

Filename

683699