arXiv subjects

Mohsen Abedi

Publications and source records attributed to Mohsen Abedi.

8 recordsLinked to original sources

arXiv2026

Communication Security via Temporal Dependency

Communication security has traditionally been built upon one of two external resources: shared secret keys or a communication advantage over the eavesdropper. However, many practical wireless scenarios, including infrastructure-less, emergency, and highly dynamic networks, cannot guarantee either resource, motivating the need for a new communication security principle. This paper introduces a new communication security paradigm that exploits temporal dependency as a security resource. Unlike conventional secrecy techniques that prevent an eavesdropper from recovering transmitted bits, the proposed paradigm allows packet decoding but prevents correct interpretation by making original and dummy packets computationally indistinguishable. Rather than protecting individual transmissions, successive transmissions are intentionally coupled so that future communication depends on correctly interpreting previous ones. As one realization, we develop a state-chained random linear network coding (RLNC) framework in which the synchronization state required to interpret each transmission block is embedded in the previous block. Therefore, synchronization failures propagate across future transmissions, resulting in persistent eavesdropper asynchronization. We analytically characterize the probability and persistence of eavesdropper asynchronization, together with the computational complexity of resynchronization, and develop transmission strategies based on transmit power and intentional-interference optimization. Numerical results demonstrate sub-second eavesdropper asynchronization under a worst- case adversarial model with no channel advantage, no secret assumptions, complete protocol knowledge, and an arbitrarily stronger eavesdropper.

math.OC↗

arXiv2026

Latency Decoupling in Low-Feedback Multi-User Networks via Overhearing-Driven NOMA

Conventional wireless protocols such as Hybrid Automatic Repeat Request (HARQ) rely on frequent and timely feedback, which becomes impractical in low-feedback regimes including non-terrestrial networks and massive IoT. This limitation is particularly critical in heterogeneous multi-user systems with unknown and asymmetric channels, where a single weak user can dominate the overall completion latency. We propose Overhearing-driven Non-Orthogonal Multiple Access (ONOMA), a novel cross-layer transmission scheme that minimizes latency without requiring instantaneous or statistical CSI at the transmitter. ONOMA integrates Random Linear Network Coding (RLNC) with symbol-aware NOMA and explicitly exploits overhearing and acknowledgment timing. In the first phase, users overhear RLNC transmissions, and the relative timing of acknowledgments is used to implicitly infer channel strength ordering. In the second phase, symbol reconstruction enables interference-free decoding for strong users, effectively decoupling user latencies. An adaptive power allocation policy is derived from acknowledgment timing-based channel estimates. Analytical and simulation results show that ONOMA outperforms TDMA, multicast, FDMA, inter-session, and classical NOMA, reducing completion time by up to 34% in two-user and 50% in larger asymmetric networks.

cs.IT↗

arXiv2025

Guaranteeing Line-of-Sight Wireless Connectivity in Stochastic Environments with Random Obstacles

Advancements in high-frequency communication technologies using millimeter waves (mmWave), Tera- Hertz (THz), and optical wireless frequency bands are key for extending wireless connectivity beyond 5G. These technologies offer a broader spectrum than the one available on low- and mid-bands, enabling ultra-high-speed data rates, higher device density, enhanced security, and improved positioning accuracy. However, their performance relies heavily on clear Line-of-Sight (LoS) conditions, as Non-LoS components are significantly weaker, making blockages a major challenge to ensure suitable received signal power. This paper addresses this limitation by identifying the minimum number and optimal placement of access points (APs) needed to ensure LoS connectivity in stochastic/dynamic environments with random obstacle locations. To achieve this, the stochastic environment is carefully modeled as a graph, where the nodes represent sub-polygons of layout realizations, and the edges capture the visibility overlaps between them. By employing maximal clique clustering and maximum clique packing methods over this graph, the proposed approach determines the AP placement locations that guarantee either full LoS coverage or controlled LoS gaps, while seamlessly adapting to the stochastic variability in obstacle locations. Simulations results in a representative stochastic environment demonstrate a 25% reduction in the required number of APs, achieving a tolerable 5% coverage gap compared to AP deployment optimized for full LoS coverage.

math.OC↗

arXiv2024

Impact of DG and survey of pricing mechanism around different states in USA

In this paper, we investigate the impact of the Distributed generation (DG) on Power Transmission Grid and pricing strategy for different geographical locations in different states, generally distributed generation (DG) on distribution feeders is known to have an impact on voltage regulation and power quality. A DG might provide voltage and power support in some cases, but most cases cause short term instability voltage, depending on the several variables, including relative DG size and location, power network and load character, so This paper also addressing to the following questions: the different between DG and conventional power station? What are penetration levels of different DG to the power grid and compliances to the IEEE relevant standards, discusses unexpected issues with a special emphasis on power protection coordination problems, potential advantage and disadvantage to using DG while Distributed Generation (DG) allows collection of energy from many sources and may provide lower environmental pollution then we will discuss what would be the main Factors affecting Electricity Prices of DG units at different states.

eess.SY↗

arXiv2023

Indoor Planning of Optical Wireless Networks for LoS Condition in Access and Backhauling

Optical wireless technology has the potential to complement the wireless access services provided so far over RF. Apart from the abundant unlicensed bandwidth available for ultra-dense deployments over optical wireless bands, optical wireless also has the potential to offer inexpensive, private, secure, and environmentally friendly communications. However, the main challenge of this technology is the inability to pass through obstacles, requiring a Line-of-Sight~(LoS) condition between transmitter and receiver. In addition, when LEDs are used to provide simultaneously wireless access and illumination, the range of the optical wireless links is notably limited. Since the typical size of Visible Light Communications~(VLC) cells is in the order of few meters, it is challenging to plan the detailed deployment of Access Points~(APs) to prevent coverage holes. This paper proposes a graph modeling approach for identifying the minimum number of APs (and their locations) for the given indoor floor plan. A connectivity tree is considered to ensure that each VLC AP can communicate with (an)other AP(s) through a LoS infrared wireless link for backhauling. The presented deployment procedure can also control the co-channel interference that is generated throughout the entire indoor environment, enhancing the data rate and illumination performance of VLC networks simultaneously.

math.OC↗

arXiv2023

Deployment of Reference Nodes to Guarantee a LoS Condition for Accurate Indoor Positioning

Accurate and precise positioning is required to guarantee the massive adoption of a wide range of 5G indoor applications, such as logistics and smart manufacturing. Native support for New Radio (NR) positioning services was included in 3GPP Rel-16, where angles-of-arrival/departure and time- (difference-)of-arrival measurements were specified in uplink and downlink. However, all these positioning techniques assume Lineof-Sight (LoS) propagation, suffering from systematic bias errors when such a condition cannot be guaranteed. To improve the accuracy and precision of indoor positioning systems that rely on proximity, triangulation, or trilateration principles, this paper considers the deployment of reference nodes to ensure LoS to one, two, or three nodes, respectively. For this purpose, the indoor service area is modeled with a graph whose nodes represent the polygons that partition the floor plan. Then, the graph is partitioned into the minimum number of cliques, which specify the minimum number of reference nodes and their placement to guarantee a LoS condition regardless the user terminal position. The desired accuracy for positioning is guaranteed by setting a minimum distance and a minimum angle between the reference nodes as two configuration parameters of the derived algorithms.

math.OC↗

arXiv2021

SWIPT-Enabled Multiple Access Channel: Effects of Decoding Cost and Non-linear EH Model

We studied power splitting-based simultaneous wireless information and power transfer (PS-SWIPT) in multiple access channels (MAC), considering the decoding cost and non-linear energy harvesting (EH) constraints at the receiving nodes to study practical limitations of an EH communication system. Under these restrictions, we formulated and analyzed the achievable rate and maximum departure regions in two well-studied scenarios, i.e., a classical PS-SWIPT MAC and a PS-SWIPT MAC with user cooperation. In the classical PS-SWIPT MAC setting, closed-form expressions for the optimal values of the PS factors are derived for two fundamental decoding schemes: simultaneous decoding and successive interference cancellation. In the PS-SWIPT MAC with user cooperation, the joint optimal power allocation for users as well as the optimal PS factor are derived. This reveals that one decoding scheme outperforms the other in the classical PS-SWIPT MAC, depending on the function type of the decoding cost. Finally, it is shown that the cooperation between users can potentially boost the performance of a PS-SWIPT MAC under decoding cost and non-linear EH constraints. Moreover, effects of the decoding cost functions, non-linear EH model and channel quality between the users are studied, and performance characteristics of the system are discussed.

cs.IT↗

arXiv2016

Optimal Energy Management for Energy Harvesting Transmitter and Receiver with Helper

We study energy harvesting (EH) transmitter and receiver, where the receiver decodes data using the harvested energy from the nature and from an independent EH node, named helper. Helper cooperates with the receiver by transferring its harvested energy to the receiver over an orthogonal fading channel. We study an offline optimal power management policy to maximize the reliable information rate. The harvested energy in all three nodes are assumed to be known. We consider four different scenarios; First, for the case that both transmitter and the receiver have batteries, we show that the optimal policy is transferring the helper harvested energy to the receiver, immediately. Next, for the case of non-battery receiver and full power transmitter, we model a virtual EH receiver with minimum energy constraint to achieve an optimal policy. Then, we consider a non-battery EH receiver and EH transmitter with battery. Finally, we derive optimal power management wherein neither the transmitter nor the receiver have batteries. We propose three iterative algorithms to compute optimal energy management policies. Numerical results are presented to corroborate the advantage of employing the helper.

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