TCH-HS activities for the GSM channel standardization

The aim of the paper is the description of the procedure adopted by ETSI to obtain the standard for the half-rate channel of the GSM system; in particular, the paper describes: i) the conditions to be tested to assess the performance of schemes proposed as candidates, for the standard, and ii) selection rules defined to rank the candidates, taking into account: average speech quality, delay and complexity. Speech quality was measured by means of subjective tests performed according to suitable test plans designed with the aim of comparing the candidates with the GSM full-rate codec. Subjective testing of hardware prototypes needs a Host Laboratory Session to process the speech material through the candidates while emulating test conditions. The paper reports the basic structure of the Host Laboratory System (HLS) and some information on its performance. Next, some information on the types of analysis performed and on the results of the analysis are illustrated and main conclusions on the fulfilment of requirements are reported. At last, the paper deals with the DTX of the GSM half-rate channel. The paper is solicited for the Technical Subject Area PCS, PCN, and Mobile Systems and Networks Personal Communications Services: (Greg Pollini)