Impact of an ARQ Scheme in the MAC/LLC Layer on Upper-layer Packet Transmissions over a Markovian Channel

In this paper, we capture the impact of an ARQ scheme in the MAC/LLC layer with a forward error-correcting code on upper-layer packet transmissions over a Markovian channel by examining the performance of a single service data unit which may be either a TCP segment or a UDP packet. We assume that the ACK/NACK delay of ARQ blocks belong to a single service data unit is less than the transmission period of each ARQ block. The performance measures of a single service data unit transmission are derived in terms of the transmission success and failure probabilities given a retransmission timeout value, retransmission timeout probability and the moments of transmission delay. Further, the queueing performance of a service data unit transmitter is also presented by varying average received signal-to-noise ratio, mobile velocity, number of ARQ blocks needed to transmit a single service data unit, number of retransmissions for each ARQ block and error-correcting capability applied to an ARQ block. From numerical examples, renegotiation between a serving base station and a mobile station is needed, when the mobile station is far from the serving base station in order that a service data unit is fragmented into a larger number of ARQ blocks in order to apply high error-correcting capability for each one.