A speech codec for the Skyphone service

Abstract

British Telecom International is to introduce an aeronautical telephone service to be known as the Skyphone. This service will use 9.6 kbit/s speech codecs because of the limited satellite power available. The codec to be used will be chosen from a number of codecs developed in several different countries. This paper gives a brief description of the Skyphone and the factors which influence the speech codec design. It then describes the codec proposed by British Telecom Research Laboratories as a candidate for the service. Subjective test results show this codec to be better than the other candidates declared to date.