Quantization Aspects in LDPC Key Reconciliation for Physical Layer Security

For physical-layer security, key reconciliation procedures are needed to correct key differences that can arise as a consequence of independent noise at the two ends of a reciprocal link. We assume either a random link in a mobile environment or use reconfigurable antenna elements to randomize the channel, such that it allows for frequent key generation. We apply LDPC codes to reconcile the keys on both sides. In here, we derive the LLRs taking into account the underlying quantization.