Asymmetric cryptography for synchronization on MIMO-OFDM system

The problem of secure communication with the multi-antenna transmission in fading channel is an essential task. The fading channel is one of media for the eavesdropper to intercept when transmitting data. We investigate method for security in wireless communication. In particular, we focus on confidential transmission of pseudo-random location of subcarrier to increase security. This security method has low implementation complexity. To make it more efficient, this research uses asymmetric cryptography algorithm for synchronization the location of subcarrier between the transmitter and receiver. This security technique has implemented in Multiple Input Multiple Output — Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system. Confidentiality and probability of interdiction is evaluated to show the security performance of the secret transmission on the rayleigh fading. The result of this paper is the proposed security scheme can protect the system from eavesdropper which result in the signals are received by the eavesdropper instead of the signals are received by the authorized receivers. In addition, in this paper we proved that security schemes using synchronization with RSA algorithms do not degrade the performance of MIMO-OFDM systems. MIMO-OFDM with security can achieve bit error rate (BER) 7.3×10⁻³ while MIMO-OFDM system without security its BER value only reach 1×10⁻², both are achieved when signal to noise ratio (SNR) = 10 dB. This can be proved by BER of MIMO-OFDM system with security is better than MIMO-OFDM system without security.

I. Introduction

The information is not secured in the wireless environment if it is compared to wired environment. So, there is need to secure data transmission. The ways to secure data transmission are by using cryptographic technologies (cryptography) or using physical layer security. For example, data can be encrypted by using certain methods that can only be read by a particular receiver. Physical layer security enables two wireless nodes to share confidential data in the presence of an eavesdropper. It is an information-theoretical construction that develops randomness at the wireless physical layer and does not need complex computation [1].