PROJECT TITLE :

Joint versus separate spectrum sensing and resource allocation in OFDMA-based cognitive radio networks

ABSTRACT:

In this study, the authors investigate the resource allocation issue for sensing-based orthogonal frequency-division multiple access (OFDMA) cognitive radio networks. They contemplate a network consisting multiple secondary users (SUs) and a secondary base station (BS) implementing a 2-phase protocol. In the primary phase, cooperative spectrum sensing is disbursed to detect the vacant subchannels. Within the second phase, SUs transmit data in the uplink to the BS by using OFDMA. They optimise the sensing parameters, transmit power and subchannel assignments jointly to minimise the overall energy consumption with the constraints on SUs’ quality of service and detection chance of the primary user. This is a mixed binary integer programming problem that is NP (non-deterministic polynomial-time)-onerous and usually intractable. They represent the problem as a bilevel drawback and propose two economical algorithms to unravel the slave and master subproblems. They conjointly study the separate optimisation, in which the sensing parameters of SUs are set irrespective of the allocated resources. They investigate the energy savings of joint versus separate optimisation using numerical experiments. The results show that the joint optimisation technique can introduce up to sixteenpercent of energy saving in zero sensing signal-to-noise ratio with the identical total transmission bandwidth of two.five MHz.