  In order to meet the constantly increasing demand by mobile terminals for
higher data rates with limited wireless spectrum resource, cognitive radio and
spectrum aggregation technologies have attracted much attention due to its
capacity in improving spectrum efficiency. Combing cognitive relay and spectrum
aggregation technologies, in this paper, we propose a dynamic spectrum
aggregation strategy based on the Markov Prediction of the state of spectrum
for the cooperatively relay networks on a multi-user and multi-relay scenario
aiming at ensuring the user channel capacity and maximizing the network
throughput. The spectrum aggregation strategy is executed through two steps.
First, predict the state of spectrum through Markov prediction. Based on the
prediction results of state of spectrum, a spectrum aggregation strategy is
proposed. Simulation results show that the spectrum prediction process can
observably lower the outage rate, and the spectrum aggregation strategy can
greatly improve the network throughput.
