Queuing analysis of the single user fading channel

In this article a different concept is proposed for measuring the performance of a communication fading channel. Information theory is usually concerned with the rate of a single codeword, whether it has infinite length (long term capacity) or finite length. The two common criteria for measuring the rate for a finite length codeword are either to consider it as a random variable (outage capacity) or as a fixed value (delay limited capacity). Yet, transmission errors occur in both approaches, requiring retransmission for reliable communication and consequently the use of a transmission buffer. From the queuing theory point of view the new system (a buffer and a fading channel) is a queue with variable rate server. Thus, the new system can be analyzed by queuing theory performance measures. Specifically we calculate the average delay of an information bit from the time it arrives at the buffer until it is successfully received. Optimization of the transmission rate for minimizing the average delay is made, resulting in a simple linear relation between the transmission rate and the total throughput