On the Sum-Rate Maximization of Integrated Communication and Secret Key Generation

This letter proposes a unified analytical framework for optimizing the sum rate of secret key generation rate (KGR) and communication rate (CR). By jointly modeling channel estimation errors’ impact on both KGR and CR, we establish a realistic performance benchmark for integrated physical-layer secret key generation (PLSKG) and communication systems. We derive asymptotic solutions for the sum-rate maximization problem, showing that optimal power allocation primarily favors the pilot symbol in the low-SNR regime, while it depends solely on the number of symbols in the high-SNR regime. Numerical results prove the communication-optimal design is also sum-rate optimal at high SNR (e.g.,