Sharif Digital Repository

Both secure and error control coding are very extensive subjects, each with a variety of subdisciplines. A secure channel coding (joint encryption-channel coding) scheme provides both data secrecy and data reliability in one process to combat problems in an insecure and unreliable channel. In this paper, a joint encryption-channel coding scheme is developed, based on concatenated turbo codes for more efficient and secure transmission of LEO satellite data. Reliability and security are achieved by adapting the pseudo-random puncturing strategy with a change of distance between satellites and ground stations in the communication séance, an issue further burdened by reducing energy consumption... 

Cooperative relaying is utilized as an efficient method for data communication in wireless sensor networks and the Internet of Things. However, sometimes due to the necessity of multi-hop relaying in such communication networks, it is challenging to guarantee the secrecy of cooperative transmissions when the relays may themselves be eavesdroppers, i.e., we may face with the untrusted relaying scenario where the relays are both necessary helpers and potential adversary. To obviate this issue, a new cooperative jamming scheme is proposed in this paper, in which the data can be confidentially communicated from the source to the destination through multiple untrusted relays. In our proposed... 

Bacterial populations are promising candidates for the development of the receiver and transmitter nanomachines for molecular communication (MC). A bacterial receiver is required to uptake the information molecules and produce the detectable molecules following a regulation mechanism. We have constructed a novel bacterial MC receiver using an inducible bacterial L-rhamnose-regulating operon. The proposed bacterial receiver produces green fluorescent protein (GFP) in response to the L-rhamnose information molecules following a quite fast regulation mechanism. To fabricate the receiver, the bacterial population has been transformed using a plasmid harboring L-rhamnose operon genes and gene... 

This paper develops a novel insight and procedure that includes a variety of algorithms for finding the best solution in a structured multi-agent system with internal communications and a global purpose. In other words, it finds the optimal communication structure among agents and the optimal policy in this structure. First, a unique reinforcement learning algorithm is proposed to find the optimal policy of each agent in a fixed structure with non-linear function approximators like artificial neural networks (ANN) and with eligibility traces. Secondly, a mechanism is presented to perform self-organization based on the information of the learned policy. Finally, an algorithm that can discover... 

The studies on forced migrants' digitally mediated communication and transnational practices have not sufficiently addressed contexts in which migrants are imposed with strong regulations on their physical mobility and information and communication technology (ICT), Internet, and social media uses. This article studied Internet and social media uses, digital divides (access, use, and the impact of Internet and social media), and digital transnational practices among Afghans in Iran. More than three million Afghans live in different legal, economic, and social positions in Iran. The analysis was based on surveys with 2003 Afghan refugees, other legally authorized Afghan immigrants, and... 

Diffusive molecular communications (DiMC) have recently gained attention as a candidate for nano- to micro- and macro-scale communications due to its simplicity and energy efficiency. As signal propagation is solely enabled by Brownian motion mechanics, DiMC faces severe inter-symbol interference (ISI), which limits reliable and high data-rate communications. Herein, recent literature on DiMC performance enhancement strategies is surveyed; key research directions are identified. Signaling design and associated design constraints are presented. Studies on fundamental information theoretic limits of DiMC channel are reviewed. Classical and novel transceiver designs are discussed with an... 

Low-latency data access is crucial in edge clouds serving autonomous vehicles. Storage I/O caching is a promising solution to deliver the desired storage performance at a reasonable cost in vehicular edge platforms. Current storage I/O caching methods, however, are not specialized for workload characteristics and demands of autonomous vehicles and/or do not consider the communication latency between the vehicle and the base station hosting the edge cloud node. In this work, we propose a storage mechanism for vehicular edge cloud platforms taking communication, I/O cache, and storage latencies into account. We evaluate our proposed framework using realistic storage traces of vehicular... 

A secure channel coding (joint encryption-channel coding) scheme provides both data security and reliability in one combined process to achieve faster processing and/or more efficient implementation. The issue of using quasi-cyclic low-density parity-check (QC-LDPC) codes in a symmetric-key secure channel coding scheme is addressed. A set of this class of LDPC codes has recently been recommended by the NASA Goddard Space Flight Center for near-earth and deep-space communications. The proposed scheme provides an efficient error performance, an acceptable level of security and a low-complexity practicable implementation. The results indicate that the proposed scheme can efficiently employ... 

In this paper, we propose a reconfigurable NoC in which a customized topology for a given application can be implemented. In this NoC, the nodes are grouped into some clusters interconnected by a reconfigurable communication infrastructure. The nodes inside a cluster are connected by a fixed topology. From the traffic management perspective, this structure benefits from the interesting characteristics of the mesh topology (efficient handling of local traffic where each node communicates with its neighbors), while avoids its drawbacks (the lack of short paths between remotely located nodes). We then present a design flow that maps the frequently communicating tasks of a given application into... 

Securing communication against non-colluding passive eavesdroppers has been extensively studied. Colluding eavesdroppers were considered for interference-limited large networks. However, collusion was not investigated for large cooperative networks. This paper closes this gap: we study the improvement the eavesdroppers achieve due to collusion in terms of the information leakage rate in a large cooperative network. We consider a dense network with nl legitimate nodes, ne eavesdroppers, and path loss exponent α ≥ 2. We show that if ne (2+2/α) (log ne)γ = o(n l) holds, for some positive γ, then zero-cost secure communication is possible; i.e., ne colluding eavesdroppers can be tolerated. This... 

Nanonetworking indicates new solutions for many applications in biomedical and industrial fields. In this paper, we examine the diffusion-based molecular communication for information transmission in nano-networks. Design of practical decoders for resource-limited nano-networks requires an understanding the fundamental performance limits of memory-limited decoders. While some existing works in the literature do consider decoders with limited memory, to best of our knowledge, the tradeoff between memory and probability of error has not been studied in the literature. In this paper we make a first step by studying this tradeoff for a particular molecular communication channel between two... 

In this paper we derive a new upper bound on the quantum key distillation capacity. This upper bound is an extension of the classical bound of Gohari and Anantharam on the source model problem. Our bound strictly improves the quantum extension of reduced intrinsic information bound of Christandl et al. Although this bound is proposed for quantum settings, it also serves as an upper bound for the special case of classical source model, and may improve the bound of Gohari and Anantharam. The problem of quantum key distillation is one in which two distant parties, Alice and Bob, and an adversary, Eve, have access to copies of quantum systems A, B, E respectively, prepared jointly according to... 

This paper considers the problem of secure data communication through the Global System for Mobile communications (GSM). The algebraic codebook method for data transmission through the Adaptive Multi Rate 12.2Kbps voice channel is investigated and its maximum achievable data rate is calculated. Based on the vocoder channel properties, the method's Bit Error Rate (BER) performance is improved by repetition coding and classification methods. Simulation results show that by simultaneous application of repetition coding and clustering methods, the decoder's performance improves about 6.5% compared to the case of no clustering for 1Kbps data communication in AMR 4.75 voice codec