Performance Analysis of RLC/MAC and LLC Layers in a GPRS Protocol Stack

In this paper, the authors analyze the performance of various layers of the General Packet Radio Service (GPRS) protocol stack, including Radio Link Control/Medium-Access Control (RLC/MAC) layer and Logical Link-Control (LLC) layer on the uplink. In the GPRS MAC protocol, several time-slotted uplink radio-frequency channels are shared by the mobiles on a request-reservation-based multiple-access scheme. Using the theory of Markov chains, they derive expressions for the average throughput and delay performance of the GPRS MAC protocol. They evaluate the performance of the RLC layer (in acknowledged mode) using Block-Level Retransmission (BLR), as defined in the current GPRS standard, and compare it with that of using Slot-Level Retransmission (SLR).