arXiv subjects

Hadi Shahriar Shahhoseini

Publications and source records attributed to Hadi Shahriar Shahhoseini.

5 recordsLinked to original sources

arXiv2024

Evaluation of Run-Time Energy Efficiency using Controlled Approximation in a RISC-V Core

The limited energy available in most embedded systems poses a significant challenge in enhancing the performance of embedded processors and microcontrollers. One promising approach to address this challenge is the use of approximate computing, which can be implemented in both hardware and software layers to balance the trade-off between performance and power consumption. In this study, the impact of dynamic hardware approximation methods on the run-time energy efficiency of a RISC-V embedded processor with specialized features for approximate computing is investigated. The results indicate that the platform achieves an average energy efficiency of 13.3 pJ/instruction at a 500MHz clock frequency adhering approximation in 45nm CMOS technology. Compared to accurate circuits and computation, the approximate computing techniques in the processing core resulted in a significant improvement of 9.21% in overall energy efficiency, 60.83% in multiplication instructions, 14.64% in execution stage, and 9.23% in overall power consumption.

cs.AR↗

arXiv2024

A Reconfigurable Approximate Computing RISC-V Platform for Fault-Tolerant Applications

The demand for energy-efficient and high performance embedded systems drives the evolution of new hardware architectures, including concepts like approximate computing. This paper presents a novel reconfigurable embedded platform named "phoeniX", using the standard RISC-V ISA, maximizing energy efficiency while maintaining acceptable application-level accuracy. The platform enables the integration of approximate circuits at the core level with diverse structures, accuracies, and timings without requiring modifications to the core, particularly in the control logic. The platform introduces novel control features, allowing configurable trade-offs between accuracy and energy consumption based on specific application requirements. To evaluate the effectiveness of the platform, experiments were conducted on a set of applications, such as image processing and Dhrystone benchmark. The core with its original execution engine, occupies 0.024mm2 of area, with average power consumption of 4.23mW at 1.1V operating voltage, average energy-efficiency of 7.85pJ per operation at 620MHz frequency in 45nm CMOS technology. The configurable platform with a highly optimized 3-stage pipelined RV32I(E)M architecture, possesses a DMIPS/MHz of 1.89, and a CPI of 1.13, showcasing remarkable capabilities for an embedded processor.

cs.AR↗

arXiv2019

An Analysis on Interactions among Secondary User and Unknown Jammer in Cognitive Radio Systems by Fictitious Play

With the advancement of communication, the spectrum shortage problem becomes a serious problem for future generations. The cognitive radio technology is proposed to address this concern. In cognitive radio networks, the secondary users can access spectrum that allocated to the primary users without interference to the operation of primary users. Using cognitive radio network raises security issues such as jamming attack. A straightforward strategy to counter the jamming attack is to switch other bands. Finding the best strategy for switching is complicated when the malicious user is unknown to the primary users. This paper uses fictitious game for analysis the defense against such an unknown jammer.

cs.CR↗

arXiv2019

Game-theory-based analysis on interactions among secondary and malicious users in coordinated jamming attack in cognitive radio systems

IEEE 802.22 standard utilizes cognitive radio (CR) techniques to allow sharing unused spectrum band. The cognitive radio is vulnerable to various attacks such as jamming attacks. This paper has focused on coordinated jamming attacks. A simple strategy for secondary users is to change their bands and switch to other appropriate bands when the jamming attack is occurred. Also, the malicious users should switch to other bands in order to jam the secondary users. To address this problem, a game theoretical method is proposed to analyze coordinated jamming attacks in CR. Then, using Nash equilibrium on the proposed game, the most appropriate bands have been found to switch as well as the optimal switching probabilities for both secondary and malicious users. Meanwhile, effects of different parameters like the number of malicious users are investigated in changing the optimal switching probabilities by analysis on the model.

cs.CR↗

arXiv2019

Defense against Lion Attack in Cognitive Radio Systems using the Markov Decision Process Approach

Cognitive Radio (CR) technology is a solution to solve the lack of spectrum by allowing the secondary user to use licensed bands. There are several potential security challenges for cognitive radio like Jamming, PUE and Lion attack. Lion attack is multi layer attacks that has effected on two layers. The Lion attack uses PUE or jamming attack in physical layer to disrupt TCP protocol in transport layer. Since transport layer is unaware of physical layer situation, when it occurs to an unacknowledged packet, there is no way to distinguish between congestion and disconnection in the physical layer. So the windows size of TCP would be decrease because of a wrong decision caused by unawareness. To Mitigate the Lion attack the cross layer design is usually used to freeze its windows size during frequency handoff. The main issue in this solution is finding the best strategy for freezing. In this paper, we propose a dynamic method for freezing and performing frequency handoff to counter Lion attack. Also a learning model based on Markov decision process (MDP) is applied. By using the proposed method, the secondary user can choose an optimal strategy in both physical and transport layers to reduce the effect of Lion attack.

cs.CR↗