Channel state based secure wireless communication

Abstract

This paper proposes a new channel state based secure wireless communication mechanism to realize secure communication with a pre-equalization function in a physical layer. Researches of physical layer security have been proposed to achieve secure communication in physical layers. On the contrary, there are a few issues where terminals in a same direction can receive a message, overhead due to complex control mechanisms, special hardware, etc. This paper focusses on practical wireless communication environment, where multi-path signals are received at a receiver. It is common knowledge that a channel state according to multi-path signals is different when a position of a receiver is different. The transmitter of proposed scheme transmits an optimized signal to a receiver with pre-equalizing the signal according to the channel state between the transmitter and the receiver. Therefore, only the receiver that has the same channel state for the pre-equalizing can obtain the high quality signal from the transmitter, and can demodulate the signal correctly. As a result, eavesdroppers around the transmitter cannot equalize the received signal before a demodulation process for the received signal because they exist at a different place of the receiver. The numerical results show that the proposed scheme can realize secure communication in typical wireless channel models. It means that a legitimate receiver can demodulate a signal correctly and eavesdroppers suffer from demodulation errors. As a result, we can find that the proposed scheme can utilize a channel state as an encryption key in physical layer security communication.