Sensing-Based SU Access Performance Study with a Four-State Markov Model in Cognitive Radios

Interference amongst radio transmissions is a key limiting factor in wireless communications. In this paper we present the results of a four state Markov model for a sensing based Secondary User access scheme and the respective derived closed form expressions. The model is primarily analysed in terms of interference and successful Secondary User transmissions, through the variation of transition probabilities and detection probabilities. The effects on interference are shown to be chiefly dependent on the probability of detection where successful Secondary User transmissions are primarily dependent on the probability of false alarm. The results and analysis introduce a baseline analysis framework of the probable spectrum conflict and wastage for a simple sensing based opportunistic access.