Research Article
Optimal Improper Gaussian Signaling for Physical Layer Security in Cognitive Radio Networks
| Symbol | Description |
| | Secondary transmit power |
| | Primary transmit power |
| | Average channel gain |
| | Path loss exponent |
| | Circular cell radius |
| | Fraction of the radius |
| | Degree of impropriety |
| | Secrecy outage probability |
| | Effective secure throughput |
| | Secure energy efficiency |
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