Method and circuit arrangement for transmitting voice signals

摘要

In the transmission of voice data by radio in the European mobile radio telephone system according to the GSM standard, 20 ms voice data are in each case transmitted as source-encoded codewords between the mobile stations and the base stations. The base stations, in turn, are connected via a narrow-band connection to a central station in which the voice decoders are arranged. Since the masking of transmission errors which could not be corrected by the channel decoder takes place in this voice decoder in the central station in the known system, only a very simple error masking capability is provided. According to the invention, more signals which characterise the reliability of the received data are derived from the channel decoder which is arranged directly at the receiver in the mobile stations and base stations, and, in dependence on these additional data, extensive different error masking measures are carried out on the received codewords. This is done not only in the mobile station but also in the base station. This then only supplies already modified codewords, characterised as error-free, to the central station which, as a result, does not need to be modified but in which only the existing simple error masking capabilities are not utilised. When the transmission is disturbed, the voice quality can thus be significantly improved without ... Original abstract incomplete. <IMAGE>