Delay distribution in a data communication system with error recovery

The aim of this paper is to evaluate the performance of an error control system with retransmission of erroneous packets, to be used in a packet switching network. As the retransmission protocol is applied link by link the system performance is calculated by considering only the link between two nodes, with an information flow in an unique direction. The system performance is characterized by the delay distribution, i.e. the distribution of the time elapsing between the sending of the first bit of an information packet and the arrival of the last bit of the error free packet. The performance of a telecommunication system is generally calculated through simulations because analytic models are not supposed to take into account all the characteristics of the actual system. On the contrary, in this paper exact mathematical models are presented, based on queueing theory, to obtain the delay distribution of the error control system, under rather general assumptions: Poisson arrivals, random errors. This model can also be used to evaluate the system in the presence of burst errors when the mean burst length and the bit error rate are low.