On the Zero-Outage Secrecy-Capacity of Dependent Fading Wiretap Channels

Area of Science:

• Information Theory
• Wireless Communications
• Signal Processing

Background:

• In slow fading Gaussian wiretap channels with independent fading, achieving positive secrecy rates is generally impossible due to non-zero outage probability.
• This limitation implies a zero secrecy capacity, hindering reliable and confidential data transmission.

Purpose of the Study:

• To characterize dependency structures enabling positive zero-outage secrecy rates (ZOSR) in wiretap channels.
• To investigate system parameters, including observations and average channel gains, that facilitate positive ZOSR.

Main Methods:

• Analysis of dependence structures in Gaussian wiretap channels with varying numbers of paths.
• Systematic global solution of zero-outage secrecy capacity (ZOSC) for finite alphabet channel gains.
• Application of the rearrangement algorithm for ZOSR with continuous channel gains.

Main Results:

• Demonstrated that specific dependence structures can achieve zero secrecy outage probability (SOP) for positive secrecy rates, enabling non-zero ZOSR.
• Identified that the legitimate link requires advantages in the number of antennas and average channel gains for positive ZOSR.
• Conjectured that the proposed dependency structure maximizes ZOSR.

Conclusions:

• Statistical dependence between channels is crucial for achieving positive ZOSR in wiretap channels.
• System parameters like receiver antennas and average channel gains significantly influence the achievability of positive ZOSR.
• Further research into optimal dependency structures is warranted.