Abstract: There is provided a physical layer security (PLS) system for enhanced cryptographic security and diversity of transmitted data, the system comprising a transmitter for first, converting the data into a plurality of OFDM symbols; second, multiplexing the plurality of OFDM symbols into parallel M OFDM streams; and third, performing spatial interleaving (SI) on the parallel M OFDM streams using a secret key. The system further comprises a receiver for receiving and de-scrambling the transmitted plurality of data samples, wherein software-defined radio (SDR) units are used as the system transmitter and receiver.

Abstract: In this work, we present a novel receiving device design for communications systems that incorporates multiple antennas at the transmitting device/receiving device. Unlike existing systems, the new system does not require prior knowledge of the channel state information (CSI) at the receiving device side to extract the information symbols from the received signal. Consequently, complexity reduction and bit error rate improvement can be jointly achieved. Moreover, the new system may offer spectral efficiency enhancement since it does not require nulling to prevent the pilot symbols as in the case of conventional systems. The results obtained show that in certain scenarios the proposed system can offer up to 15 dB of bit error rate improvement over conventional systems. Moreover, the new system can provide about 16.6% of the spectral efficiency improvement.

Abstract: A chaotic cryptographic technique for orthogonal frequency division multiplexing (OFDM) based wireless/wired communication systems is implemented with an OFDM symbol structure based on symmetric key cryptography. At the receiver side, data detection becomes infeasible without knowledge of the secret key. Without the knowledge of the key, the signal will be a noise-like signal. The computational power required to implement the technique is very low, rendering the system an attractive option for high data rate communications based on OFDM technology. The system security is proportional to (L×N)! where N is the number of subcarriers in the OFDM system and L is the number of OFDM symbols involved in the encryption process. For OFDM applications where ?256, L may be set to 1 and breaking the system would require N! exhaustive-search trials. In the case that N<256, L may be increased.

Abstract: A chaotic cryptographic technique for orthogonal frequency division multiplexing (OFDM) based wireless/wired communication systems is implemented with an OFDM symbol structure based on symmetric key cryptography. At the receiver side, data detection becomes infeasible without knowledge of the secret key. Without the knowledge of the key, the signal will be a noise-like signal. The computational power required to implement the technique is very low, rendering the system an attractive option for high data rate communications based on OFDM technology. The system security is proportional to (L×N)! where N is the number of subcarriers in the OFDM system and L is the number of OFDM symbols involved in the encryption process. For OFDM applications where ?256, L may be set to 1 and breaking the system would require N! exhaustive-search trials. In the case that N<256, L may be increased.