Wireless Communication System With N-states Markov Chain

In this paper, two kinds of discrete-time queueing systems have been discussed. In the first model, an MMBP/Geo/1queue with correlated positive and negative arrivals is studied. In the infinite-capacity queueing system, positive customers and negative customers are generated by a Bernoulli source with two correlated geometrically distributed periods. During the positive and negative periods, positive and negative customers arrive to the system according to two different geometrical arrival processes. Under the late arrival scheme (LAS), two removal disciplines caused by negative customers are investigated in the paper. In individual removal scheme, a negative customer removes a positive customer in service if any, while in disaster model, a negative customer removes all positive customers in the system if any. The negative arrival has no effect on the system if it finds the system empty. We analyze the Markov chains underlying the queueing systems and evaluate the performance of two systems based on generating functions technique. Some explicit solutions of the system, such as the average buffer content and the stationary probabilities are obtained. The effect of several parameters on the system performance is shown numerically.In the second one, we investigate a type-II hybrid Automatic Repeat request (ARQ2) system with two kinds of channel. Packets with fixed transmission time arrive according to a geometrical arrival process. Due to the error-prone nature of the channel, the receiver may decode the packet unsuccessfully and then send a negative acknowledgement to the sender in order to receive the packet once more. Under the restriction that the retransmission times cannot exceed a given number, the sender will retransmit the packet with a recoding scheme. In this scheme, an error-detecting code and a half-rate invertible code for error correction are used to accomplish the retransmission. We analyze the Markov chain underlying the queueing system and evaluate the performance of the system. The impact of the arrival rate and the SNR on the packet delay, packet loss probability and throughput has been investigated. Some numerical examples are given to show the characteristics of the system.