SUMMARY
In the cognitive radio (CR) system where spectrum sensing and data transmissions are performed simultaneously, the proper selection of frame duration (t) is of utmost importance. Small t leads to an increased false alarm probability while large value of it delays implementation of sensing decision of the current frame to the next. The former case decreases the achievable throughput of the CR user while latter one may disturb the licensed user communication. Under the constraints of maintaining a target detection probability of dP, this paper attempts to design a frame duration t where achieved throughput of the CR system is maximised. To do so, an analysis of achievable throughput with t was performed which reveals that, initially, with the increase in t, the achievable throughput increases sharply, but after its certain value, the increments are negligible and achievable throughput appears to maintain a constant value. The performed analysis shows that, it is not possible to perfectly optimize t, however, a close optimisation can still be performed which can maximise the achievable throughput. From the realistic point of view, the CR system is further modelled under uncertain noise conditions. The achieved simulation results well justify the presented analysis.Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 312-318, DOI: http://dx.doi.org/10.14429/dsj.65.8739