New physical layer key generation dimensions: Subcarrier indices/positions-based key generation

In this letter, novel algorithms for secret key generation from the wireless channel in multi-carrier systems are proposed for ensuring the confidentiality and authentication in wireless communication systems. The novelty of the proposed algorithms lies in the generation of random secret bits not just from the magnitudes of orthogonal frequency division multiplexing (OFDM) subchannels as it has conventionally been done in the literature, but also from the indices/positions of the subchannels corresponding to highest gains. Thus, the proposed algorithms provide additional dimensions for enhancing overall key rates. The efficiency of the proposed algorithms is evaluated in terms of key mismatch rate (KMR) and key generation rate (KGR). Simulation results showed that the proposed algorithms can enhance the overall performance of physical layer key-based algorithms by providing extra dimensions for secret key generation.