Impact of end to end encryption on GSM speech transmission quality - a case study

A method has been developed to perform perceptual measurement of speech quality for low bit rate voice coders. This technique is suitable for quantitative measurements of speech quality provided by mobile terminals supporting end to end encryption. Analysis of speech quality not only gives a measure of the service provided to the users, it may also serve as an indication of difficulties within the end to end transmission network. As end to end security moves increasing towards frameworks and protocols for heterogeneous networks the impact of network access mechanisms and network transitions will have an effect. This effect may not only be on the ´yes/no´ provision of an encrypted voice service, but also on the speech quality which users´ experience. This paper presents a mechanism to quantitatively evaluate the quality of speech which is suitable for end-to-end encrypted mobile communication systems.