A packet radio protocol for group communication suitable for the GSM mobile radio network

GSM is in use in many European countries mainly to provide point-to-point telephone conversation and mobile data services. GSM only offers circuit switched services on the air interface (GSM phase 2). Future digital mobile radio systems based on TDMA (TETRA, UMTS, ...) will use a packet access mechanism, which is known to give a better utilisation of the transmission medium in case of bursty traffic. A packet access mechanism within GSM could provide several new services as medium, high and variable bit rate services which are required in fields as railway and road transport informatics and mobile data communication. Some different proposals for a packet radio service suitable for GSM are discussed in this paper. A packet access protocol suitable for GSM was developed and analysed by simulation. Radio wave propagation and the resulting bit errors are taken into account by modelling the channel according to a Rayleigh fading channel.