A Non-Time-Limited Channel Sounding Protocol for Key Generation

The traditional channel sounding protocol requires that the whole sounding process must be completed within a coherent time. When the communication delay is close to or greater than the coherent time, the protocol will not work properly. In order to solve this problem, a novel Non-Time-Limited channel sounding protocol is proposed. The proposed channel sounding protocol does not need to guarantee the channel reciprocity, has no limit on the communication delay and has strong multi-relay scalability. At the same time, a relay-assisted security extension mechanism is proposed to prevent the collaborative eavesdropping of the neighboring attackers. Simulation experiments show that the Non-Time-Limited channel sounding protocol can get rid of the influence of channel change speed on key generation, effectively improve key consistency in high-speed mobile scenarios, and still maintain good key agreement rate performance in underwater acoustic communication.