Packet-Chains for Physical Layer Security of Wireless Communications

This article introduces a resilient and lowcomplexity transmission scheme designed to enhance physicallayer security against eavesdropping in wireless systems. Unlike conventional approaches, where data packets are transmitted independently, the proposed method sequentially combines multiple consecutive packets into a secure packet chain, in which each packet depends on its predecessor. Consequently, the content of any individual packet cannot be reliably reconstructed without access to the initial packet in the chain whose contents are masked to prevent unauthorized interference cancellation. Additionally, the masked first packet is utilized to vary the power and phase of transmitted symbols, introducing variations that further degrade the eavesdropper's decoding capability. Analytical expressions are derived for key performance metrics, such as the secrecy outage probability (SOP) and bit error rate (BER), to evaluate the system performance. The obtained analytical results, corroborated by simulation results, confirm that the packet chains maintain consistently low SOP across a wide range of signal-to-noise ratios (SNRs), while driving the eavesdropper's BER toward 0.5, rendering the intercepted data statistically indistinguishable from random noise.