For the very first time, we present the use of optical chaos for the secure transmission of electroencephalogram (EEG) signals through optical fiber medium in remote health monitoring systems. In our proposed scheme, a semiconductor laser source is used to generate optical chaos, which hides EEG signal before its transmission over the optical fiber medium. The EEG signals are acquired by using a 14channel Emotiv headset device, which are then processed and rescaled to be compatible with the experimental environment (Optisystem). The mixing of EEG signals and chaos is performed using additive chaos masking scheme, which exhibits certain useful properties such as simplicity and easy recovery of the message. Chaotic data (a combination of EEG signals and chaos) is sent over the optical fiber medium to investigate propagation issues associated with secure EEG signal transmission. The scheme is implemented for long haul communication in which the linear impairments of optical fiber are controlled for successful transmission of the secure signal. The parameters at transmitting and receiving sides are selected to achieve synchronization, such that the transmitted signal could be subtracted from identical chaos to restore the original EEG signal at the receiving side. The scheme is tested for different lengths of the optical fiber cable in which the quality of the received signal is determined by obtaining Q-factors. This scheme could also be used with medical signals such as electrocardiography and electromyography.INDEX TERMS EEG signal, Emotiv, semiconductor laser, optical chaos, additive chaos masking, synchronization, remote health monitoring, long haul.

The demand for remote health monitoring will significantly increase in the near future due to a decrease in the doctor/patient ratio as the world population grows. In remote health monitoring, one of the major goals is to send patient's data to clinical experts at geographically distant locations. In this scenario, the importance of implementing security on patients' clinical information increases, so that this could not be either changed or read by an unauthorized person. Rivest Cipher (RC5) algorithm is a secure and simple encryption algorithm. Due to its simplicity, fast encryption, and low memory requirements, it is considered as a suitable block cipher for resource constraint environments, such as body area networks (BAN), although it can be broken by various attacks due to poor diffusion. In this paper, we propose a chaotic-based key scheduling algorithm for the RC5 in which round keys are generated based on 2-D chaotic maps and used as a symmetric key during the encryption and decryption process. Cipher feedback mode is adapted to further increase the diffusion property of the cipher. This chaos-based key is very difficult to trace, and the cipher is extremely hard to break. A strict security analysis of the proposed cipher is performed against several attacks. The experimental results have shown that the impact of this approach is significantly better than the conventional security mechanisms in case of BAN when applied to critical clinical images.INDEX TERMS Remote health monitoring, encryption, clinical images, wireless body area networks (WBAN), RC5, 2D-chaotic map.

Free-space optical (FSO) communication is one of the choice of researchers for most of the bandwidth hungry applications in evolving networks where the deployment of optical fiber is not directly possible as a transmission medium. In this research article, benefits, challenges, applications and role of FSO is discussed in detail for evolving networks. Further, performance of FSO communication system is tested using four channels of dense wavelength division multiplexing (DWDM). Various simulations are performed on FSO including different weather conditions, that directly affect the link performance. Many important parameters such as distance, data rate, bit error rate, amplifier gain, transmitter power, and attenuation under different weather conditions are tested in this research work. The operation of FSO communication system is carried out in the range 760-850 nm where equal channel spacing is considered for the working of DWDM communication system. Moreover, a fair comparison of proposed system is also presented for its operation in two more bands i.e. C and L-band, to show which one offers better performance. Simulation are performed in licensed version of Optisystem 14.0 and MATLAB. For the analysis of proposed system, results are presented in the form of BER and Q-factor plots.

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Radio over fiber (RoF) has found to be one of the most effective communication techniques. It has the tendency to incorporate both optical fiber and free space radio paths. In this research article, importance, benefits, and applications of RoF system are discussed in detail for futuristic networks. The performance of RoF system is visualized by modulating the data with the RF signal having same frequency at both transmitter and receiver ends. Initially, the performance is checked using non-return to zero (NRZ) format and later compared with duobinary (DB) and carrier suppressed return to zero (CSRZ). Various simulations are performed which directly affect the system performance. Important parameters such as RoF link distance, data rate, transmitter power, amplifier gain, and RF signal frequency are tested. The operation is carried out at 1550 nm wavelength and 30 GHz RF frequency. System is optimized to receive the transmitted waveforms successfully. Simulations are performed in Optisystem 17.0 and MATLAB. For the analysis, the results are plotted using Q-factor and BER values.