Digital short range radio: channel coding and synchronisation for speech using the GSM codec

Digital short range radio (DSRR) initially came into being in the UK as a result of an EEA (electronic engineering association) initiative. Originally known as the `private advanced radio service´ (or `PARS´), DSRR is now an ETSI draft interim ETS thus promoting it as a European standard. DSRR has adopted the use of the GSM speech coding algorithm developed for the panEuropean digital cellular service. This has a net bit rate of 13 kbits/sec, thus leaving 3 kbits/sec for frame synchronisation and channel coding. Due to the GSM gross channel bit rate being 22.8 kbits/sec, it was not possible to utilise the GSM channel coding, and a scheme specifically for DSRR had to be developed. However, an initial channel coding and synchronisation scheme based on that devised for GSM was implemented on the breadboard demonstrators. This paper describes the development of the channel coding and frame synchronisation scheme for DSRR