Power Allocation Strategy for Secret Key Generation Method in Wireless Communications

Secret key generation (SKG) is an emerging technology to secure
wireless communication from attackers. Therefore, the SKG at the physical
layer is an alternate solution over traditional cryptographic methods due to
wireless channels’ uncertainty. However, the physical layer secret key generation (PHY-SKG) depends on two fundamental parameters, i.e., coherence time
and power allocation. The coherence time for PHY-SKG is not applicable to
secure wireless channels. This is because coherence time is for a certain period
of time. Thus, legitimate users generate the secret keys (SKs) with a shorter key
length in size. Hence, an attacker can quickly get information about the SKs.
Consequently, the attacker can easily get valuable information from authentic
users. Therefore, we considered the scheme of power allocation to enhance the
secret key generation rate (SKGR) between legitimate users. Hence, we propose an alternative method, i.e., a power allocation, to improve the SKGR. Our
results show 72% higher SKGR in bits/sec by increasing power transmission.
In addition, the power transmission is based on two important parameters,
i.e., epsilon and power loss factor, as given in power transmission equations.
We found out that a higher value of epsilon impacts power transmission and
subsequently impacts the SKGR. The SKGR is approximately 40.7% greater
at 250 from 50 mW at epsilon = 1. The value of SKGR is reduced to 18.5%
at 250 mW when epsilonis 0.5. Furthermore, the transmission power is also
measured against the different power loss factor values, i.e., 3.5, 3, and 2.5,
respectively, at epsilon = 0.5. Hence, it is concluded that the value of epsilon and power loss factor impacts power transmission and, consequently, impacts
the SKGR.