This paper considers the primary user activity or the subchannel availability in optimally
distributing the available resources for an orthogonal frequency-division multiple-access
(OFDMA) cognitive radio multicast network. For this purpose, a risk-return model is
presented, and a general rate-loss function, which gives a reduction in the attainable
throughput whenever primary users reoccupy the temporarily accessible subchannels, is
introduced. Taking the maximization of the expected sum rate of secondary multicast groups …

In cognitive radio networks with the coexistence of primary and secondary users, the
problem of how to optimally allocate available resources (eg, bandwidth and power) to
multicast groups of secondary users that use orthogonal frequency division multiplexing
(OFDM) is important. Taking the maximization of the weighted sum rate of such groups as
the design objective, we propose a practically optimal subcarrier and power allocation
scheme under constraints on the tolerable interference thresholds at individual primary …