Computer Engineering Department

The Global System for Mobile Communications (GSM) Phase 2+ standard specifies a type of packet data service called General Packet Radio Service (GPRS). GPRS allows dynamic allocation of bandwidth resources. Wireless channels are allocated to a Mobile Station based on its demand. A communication session may last for an extended period of time with intermittent packet transmissions. This paper investigates the throughput and buffer utilization in a GPRS network under popular Internet traffic models, such as WWW and e-mail (SMTP) suppose the (Logical Link Control) LLC and (Radio Link Control/Medium Access Control) RLC/MAC layers in GPRS. The layers work either in acknowledged (Transparent) or not-acknowledged (non-Transparent) mode. We propose a new protocol for the acknowledged mode of LLC layer. We name this mechanism “channel dependent LLC protocol”. The new protocol dynamically takes in to consideration the quality of wireless channel. When the channel is in good quality, the transmission is allowed. And the transmission can not take place while the channel is not in a good condition.