One Directional Real-Time Traffic Flows over the GPRS Air Interface

Packet-switched non real-time data transmissions have increased a lot in the fixed network. Circuit-switched based cellular transmission techno logy Global System for Mobile communications (GSM) is already in the service for more than a decade. A packet based transmission system called General Packet Radio Services (GPRS) is developed for non real-time packet data transmission system by the evolution of existing GSM network. Now question may arise, can GPRS be used for real-time traffic transmission, although it was not designed for it? Of course, typical realtime traffic such as voice conversation may not be optimized in GPRS system. But one directional real-time traffic such as teacher’s voice for students, leaders’ command for the followers etc. can be transmitted over GPRS. The ‘activity factor’ of real-time terminals has significant impact on the traffic channel efficiency. Traffic channel efficiency with a bursty one directional real-time traffic is unacceptably low, especially with the range of acceptable call loss probabilities pertaining to a lower activity factor. The channel efficiency can be enhanced and the call loss probability can be suppressed significantly if a higher maximum number of calls are accepted. A complete analysis without RLC/MAC block dropping, and with RLC/MAC block dropping that increases the channel efficiency is executed. Results show that the channel efficiency as well as the RLC/MAC block dropping probability increases with increasing call intensity, maximum number of admitted calls and the activity factor.