Amr Mokhtar

A simple 8-bit digital microcontroller implementation for chaotic sequence generation

This paper introduces a simple implementation of digital chaotic sequence generator. The implementation is based on using microcontroller ATMGA 16 to generate the chaotic map required for advanced encryption standard (AES) encryption scheme s-box and radar frequency agile control. The implemented circuit is simple, low cost and suitable for use with identification friend or foe (IFF) equipped with data encryption systems. The circuit also can changes the carrier frequency of the transmitted signal based on chaotic map, benefits a security and confidentiality to the radar waveform against Electronic Counter Measurement (ECM). The circuit generates 256 random sequences at different initial conditions and each of them has 256 sequences generated from different bifurcation parameters. The circuit is simulated under Matlab program environment and Proteus circuit simulation program. A security analysis for the implemented circuit is demonstrated. The results show the superiority of the circuit for generating the random sequences forming an efficient s-box for IFF system and radar frequency agility.

Cooperative cognitive radio network with energy harvesting: Stability analysis

This paper investigates the maximum stable throughput of a cooperative cognitive radio system with energy harvesting Primary user (PU) and Secondary user (SU). Each PU and SU has a data queue for data storage and a battery for energy storage. These batteries harvest energy from the environment and store it for data transmission in next time slots. The SU is allowed to access the PU channel only when the PU is idle. The SU cooperates with the PU for its data transmission, getting mutual benefits for both users, such that, the PU exploits the SU power to relay a fraction of its undelivered packets, and the SU gets more opportunities to access idle time slots. To characterize the systems stable throughput region, it is noted that the queues in the system are interacting, i.e., the service process of any queue depends on the current state of the other queues, which renders the analysis intractable. To simplify the analysis, a dominant system approach is used to obtain a closed form expressions for the systems stable throughput region. Results reveal that, the non-cooperative system outperforms the cooperative system for low SU energy harvesting rate and irrespective of the PU energy harvesting rate, while the cooperation benefits are seen for high SU energy harvesting rate.

Simulation of pulse compression performance under influence of background noise in modern surveillance radar

In this paper, simulation of pulse compression performance in radar systems under influence of Gaussian noise and low angle Weibull land clutter have been presented. Peak side lobes (PSL) of optimized biphase pulse compression codes (OBPCC) of lengths ranging between 5-30 have been discussed. Optimization of peak side lobes is processed using Genetic algorithm optimization tool. Simulation of pulse compression performance at signal to noise ratio (S/N) varying between 5 to 30 dB is introduced. Comparative study shows that for low values of S/N, the peak side lobe level for OBPCC under influence of background noise is equal to its correspondence of ideal biphase codes used in pulse compression radar, leading to enhancement of detection capability, range resolution and compression ratio of modern surveillance radar systems.

Towards physical layer security in Internet of Things based on reconfigurable multiband diversification

Numerous IoT devices in wireless network interact and cooperate with each other to achieve diverse intelligent services. Such devices use static channel for wireless transmission, making the whole network vulnerable to eavesdroppers. This raises a need for means to allow secure data transmission/reception between IoT routing nodes. The concept of antenna diversity is used to enhance secrecy capacity by expanding the channel bandwidth trying to confuse attackers. Therefore, an efficient solution is considered by using multiband signal transmitter circuit to enable frequency-manipulation between connected devices. In this paper, we conducted security evaluation based on optimal relay selection protocols to maximize the channel secrecy capacity and improve data transmission. This approach uses channel sensing metric to manipulate the transmission characteristics between legitimate users via changing the operating frequency and bandwidth. Results showed a massive improvement in physical layer security against eavesdropping attack when using reconfigurable frequency bands.

Security versus reliability study for power-limited mobile IoT devices

Internet of Things (IoT) depicts an intelligent future, where any IoT-based devices having a sensorial and computing capabilities to interact with each other. Recently, we are living in the area of internet and rapidly moving towards a smart planet where devices are capable to be connected to each other. Cooperative ad-hoc vehicle systems are the main driving force for the actualization of IoT-based concept. Vehicular Ad-hoc Network (VANET) is considered as a promising platform for the intelligent wireless communication system. This paper presents and analyzes the tradeoffs between the security and reliability of the IoT-based VANET system in the presence of eavesdropping attacks using smart vehicle relays based on opportunistic relay selection (ORS) scheme. Then, the optimization of the distance between the source (S), destination (D), and Eavesdropper (E) is illustrated in details, showing the effect of this parameter on the IoT-based network. In order to improve the SRT, we quantify the attainable SRT improvement with variable distances between IoT-based nodes. It is shown that given the maximum tolerable Intercept Probability (IP), the Outage Probability (OP) of our proposed model approaches zero for Ge → ∞, where Ge is distance ratio between S — E via the vehicle relay (R).

A Computational Offloading Framework for Object Detection in Mobile Devices

Recently, the role of mobile devices has changed from a calling or entertaining device to a tool for making life easier. However, this growing role is associated with extensive computing requirements to execute tasks such as object detection. Moreover, executing heavy tasks in a mobile with limited resources takes a long processing time and consumes much energy. This paper presents a computational offloading framework to improve the performance of object detection tasks. The framework uses a simple decision model to select between local processing and offloading based on the network context. A demo has been developed to evaluate the framework performance. The experimental work includes different image sizes and employs 3G and Wi-Fi networks. The results show a response time speedup that could reach five times for small images and 1.5 times for big images. The energy saving also ranges from 80% to 50%. Furthermore, offloading through a Wi-Fi network shows more performance stability than a 3G network. Finally, results demonstrate that offloading the object detection computation decreases the memory allocations to less than 1% in comparison with local processing.

Optimized DC-free turbo coding scheme under the map decoding algorithm

A useful tool in the design of reliable digital communication systems is channel coding. Turbo codes have been shown to yield an outstanding coding gain close to theoretical limits in the additive white Gaussian noise (AWGN) channel. In this paper, we applied Wadayamapsilas schemes of the direct current DC-free codes in a cascaded structure with turbo codes under the Maximum a Posteriori (MAP) decoding algorithm. The work done by Deng and Herro [1] impose relatively strong restrictions on the decomposition of the codeword. Wadayama removed such restrictions to treat any decomposition of the codeword. This is the main difference between the two approaches and it is why we used Wadayamapsilas. The proposed scheme achieves the DC-free coding and error-correcting capability simultaneously. A given sequence becomes DC-free if and only if the absolute Running Digital Sum (RDS) value of the sequence is bounded by a constant for any time instant. The RDS control encoder generates a sequence giving the turbo coded sequence a bounded RDS value which results in a high error correcting capability. The high performances in terms of Bit Error Rate (BER) which is very close to the Shannon limits of this simple cascaded structure allows us to expect a new results with other capacity approaching EC block codes, such as low density parity check codes.