Hybridization of OFDMand Physical Layer Techniques for Information Security in Wireless System

Due to quest for high data rate, reliable and secure communication, this has motivated both wired and wireless network access service providers to deploy a next-generation network with ability to meet the required need. The use orthogonal frequency division multiplexing(OFDM) enables reliable transmission of various data traffic by optimizing subcarrier, power, and allocation of bits among different users. Traditionally, securing data in wireless system is always at the upper layer of open system interconnection(OSI) Model by using data encryption techniques. However, such techniques may not be acceptable for future decentralized networks due to their high complexity in implementation and computation. In this work, an OFDM IEEE 802.11a wireless system is used and physical layer encryption (PLE) schemes are implemented in securing the information transfer between two legitimate parties. In the simulation, the source data are encrypted by obfuscation with dummy data in between the encrypted data of which 52 subcarriers were considered of which 25 subcarriers are reserved for dummy data and 27 were for data. The simulation was conducted for four different modulation techniques i.e., BPSK, QPSK, 16 QAM, and 64 QAM. The result obtained shown that for all the modulation schemes, the key rate increases with an increase in the reserved subcarrier bits. Also ,the security level increased when substantial percentages of the subcarriers are reserved for dummy data