adio-direction finding has gained a lot of interest in recent years especially on the VHF and UHF bands. There are many different approaches to determining the origin of a radio transmission. Each approach has its advantages and disadvantages. An experienced RDFer learns to make use of several methods to master the art. Directional antennas with good front-to-back ratios (such as a Yagi or quad...

This paper considers physical-layer security protocols in multicast cognitive radio (CR) networks. In particular, we propose dual-hop cooperative decode-and-forward (DF) and randomize-and-forward (RF) schemes using partial relay selection method to enhance secrecy performance for secondary networks. In the DF protocol, the secondary relay would use same codebook with the secondary source to for...