Energy-Efficient Ant Colony Task Assignment Based Spectrum Sensing for Cognitive Radios

In this paper, we discuss the energy efficiency (EE) of an ant colony task assignment-based cooperative spectrum sensing (CSS) algorithm for cogntive radios. The main idea in this technique, called the 2EACRAC2S algorithm, is that a secondary (SU) participates in the CSS procedure only when the path loss between itself and the primary user (PU) exceeds a threshold. Otherwise, it does not carry out SS and refrains from sending the decision to a fusion center (FC), which saves energy. The FC uses the AND fusion rule to combine the decisions from active SUs. Expressions for the achievable throughput, energy consumption and EE of the 2EACRAC2S algorithm are derived. Results based on numerical techniques show that the 2EACRAC2S outperforms CSS technique, in terms of EE.