Dynamic resource allocation in OFDM based cognitive radio system considering primary user QoS and secondary user proportional constraints

Abstract

The spectrum underutilization can be overcome by the use of cognitive radio systems. A cognitive radio can intelligently allocate the unused spectrum of licensed user to the unlicensed user without giving any interference to the former and thereby and improved spectrum efficiency can be achieved. Cognitive radio is an artificial intelligent wireless technology which can allocate the licensed user channels to the unlicensed users without disturbing the licensed users thereby improving the spectrum efficiency. In this paper, we concentrate on an orthogonal frequency division multiplexing (OFDM) based cognitive radio (CR). In a conventional OFDM system, the capacity is maximized using water filling algorithm. In this paper we jointly optimize the power and subcarrier allocation for OFDM based CR system in a multiuser environment. In addition to this we introduce the proportionality rate constraints. On the implementation of this, we achieve higher data rate with significantly low complexity.