Achievable Rate Regions for Two-Way Relay Channel using Nested Lattice Coding

This paper studies Gaussian Two-Way Relay Channel where two communication nodes exchange messages with each other via a relay. It is assumed that all nodes operate in half duplex mode without any direct link between the communication nodes. A compress-and-forward relaying strategy using nested lattice codes is first proposed. Then, the proposed scheme is improved by performing a layered coding : a common layer is decoded by both receivers and a refinement layer is recovered only by the receiver which has the best channel conditions. The achievable rates of the new scheme are characterized and are shown to be higher than those provided by the decode-and-forward strategy in some regions.Comment: 27 pages, 13 figures, Submitted to IEEE Transactions on Wireless Communications (October 2013

Energy minimization based Resource Scheduling for Strict Delay Constrained Wireless Communications

This paper investigates the energy consumption minimization for resource scheduling in a wireless communication. We propose to take into account a strict delay constraint for each queued packet rather than an average delay constraint, in addition to a buffer overflow constraint. The associated optimization problem can be modeled as Constraint Markov Decision Problem where the actions are the number of packets sent on the known channel at each slot. The optimal random policy is exhibited through the resolution of standard linear programming. We show the gain in energy is substantial compared to naive policy

Testing Against Independence with an Eavesdropper

We study a distributed binary hypothesis testing (HT) problem with communication and security constraints, involving three parties: a remote sensor called Alice, a legitimate decision centre called Bob, and an eavesdropper called Eve, all having their own source observations. In this system, Alice conveys a rate R description of her observation to Bob, and Bob performs a binary hypothesis test on the joint distribution underlying his and Alice's observations. The goal of Alice and Bob is to maximise the exponential decay of Bob's miss-detection (type II-error) probability under two constraints: Bob's false alarm-probability (type-I error) probability has to stay below a given threshold and Eve's uncertainty (equivocation) about Alice's observations should stay above a given security threshold even when Eve learns Alice's message. For the special case of testing against independence, we characterise the largest possible type-II error exponent under the described type-I error probability and security constraints.Comment: submitted to ITW 202

Multi-library Coded Caching with Partial Secrecy

International audienceThe paper considers a coded caching setup with two libraries and where only one of them needs to be kept secret from an external eavesdropper. We provide upper and lower bounds on the secrecy rate-memory tradeoff for systems with K = 2 or K = 3 receivers. Our bounds are tight in some regimes and show that the standard (non-secure) coded caching upper bound can be approached for a wide range of parameters. In some cases, the proposed upper bound on the secrecy rate-memory tradeoff is even lower than the lower bound for standard coded caching. The reason is that in our setup the ratio of receivers requesting secure files over those requesting nonsecure files is fixed and known to everyone in advance. The transmitter can thus adjust the contents stored in the cache memories to this ratio

On the energy efficiency of base station cooperation under limited backhaul capacity

A part of this work is published in the IEEE 3rd International Conference on Communications and Networking (ComNet’2012)International audienceRecently, energy-efficient (EE) communications have received increasing interest specially in cellular networks. Promising techniques, such as multiple input multiple output (MIMO) and base station (BS) cooperation schemes, have been widely studied in the past to improve the spectral efficiency and the reliability. Nowadays, the purpose is to investigate how these techniques can reduce the energy consumption of the systems. In this paper, we address for a single-user scenario, the energy efficiency of two BSs cooperation under limited backhaul capacity. In order to evaluate the EE metric, we provide first an information-theoretical analysis based on the outage probability, for a quantization model over the backhaul. Then, we extend this EE analysis to a more practical approach with data transmission over the backhaul. For both approaches, we identify by numerical/simulation results the cooperation scenarios that can save energy depending on the backhaul capacity

Mixing a Covert and a Non-Covert User

This paper establishes the fundamental limits of a two-user single-receiver system where communication from User 1 (but not from User 2) needs to be undetectable to an external warden. Our fundamental limits show a tradeoff between the highest rates (or square-root rates) that are simultaneously achievable for the two users. Moreover, coded time-sharing for both users is fundamentally required on most channels, which distinguishes this setup from the more classical setups with either only covert users or only non-covert users. Interestingly, the presence of a non-covert user can be beneficial for improving the covert capacity of the other user.Comment: Accepted to 2023 IEEE International Symposium on Information Theory (ISIT

Joint Resource Scheduling and Computation Offloading for Energy Harvesting Communications

International audienceThis paper studies the joint optimization of resource scheduling and computation offloading for mobile networks where energy harvesting (EH)-enabled devices are wirelessly connected to nearby base stations (BSs), which can be endowed with some computational capabilities. We consider that a mobile device may run its applications either locally or remotely at its serving base station. We also consider that its applications are strict delay constraints. Our objective is to minimize the packets' loss due to buffer overflow or delay violation of the queued packets at the mobile device. We formulate this problem as a Markov Decision Process (MDP) and exhibit an optimal deterministic offline scheduling-offloading policy. This policy makes decision on the processing location (either local or offloading) and on the number of processed packets by relying on the knowledge on the current channel, the past data and energy arrivals as well as the harvested energy available in the battery. We show through numerical results that the proposed policy can significantly improve the successfully received packets' rate and the energy consumption compared to other policies, such as immediate scheduling or only local processing or only offloading policies

Efficient network representation for GNN-based intrusion detection

International Conference on Applied Cryptography and Network Security (ACNS 2023)International audienceThe last decades have seen a growth in the number of cyber-attacks with severe economic and privacy damages, which reveals the need for network intrusion detection approaches to assist in preventing cyber-attacks and reducing their risks. In this work, we propose a novel network representation as a graph of flows that aims to provide relevant topological information for the intrusion detection task, such as malicious behavior patterns, the relation between phases of multi-step attacks, and the relation between spoofed and pre-spoofed attackers’ activities. In addition, we present a Graph Neural Network (GNN) based-framework responsible for exploiting the proposed graph structure to classify communication flows by assigning them a maliciousness score. The framework comprises three main steps that aim to embed nodes’ features and learn relevant attack patterns from the network representation. Finally, we highlight a potential data leakage issue with classical evaluation procedures and suggest a solution to ensure a reliable validation of intrusion detection systems’ performance. We implement the proposed framework and prove that exploiting the flow-based graph structure outperforms the classical machine learning-based and the previous GNN-based solutions

Decentralized Coded Caching for Wiretap Broadcast Channels

International audienceWe consider a K-receiver wiretap broadcast channel where Kw receivers are weak and have cache memories and Ks receivers are strong and have no cache memories. We derive an upper bound on the secrecy rate-memory tradeoff under a joint secrecy constraint and under decentralized caching. In contrast to previous works, prefetching in our scheme is purely decentralized and receivers randomly sample from a random key stream available at the transmitter and from the files in a library. For small cache sizes, the performance of our scheme improves with increasing length of the random key stream. For moderate and large cache sizes, a small key stream suffices to perform close to the information-theoretic limit of the system

Packet Scheduling and Computation Offloading for Energy Harvesting Devices without CSIT

Virtual conferenceInternational audienceThis paper proposes a joint packet scheduling and computation offloading policy for an Energy Harvesting (EH) mobile terminal wirelessly connected to a Base Station (BS) when the channel between the mobile and the BS is unavailable at the mobile side. The mobile terminal has to decide if its packet related to one application is computed either locally or remotely by the BS within a strict delay imposed by this application without knowing the channel in advance. Our objective is to guarantee reliable communication by minimizing the packet loss. This packet loss is due to buffer overflow, strict delay violation and channel mismatch. We formulate the problem using a Markov Decision Process (MDP) and we propose and implement the optimal deterministic offline policy to solve it. This optimal policy decides: (i) the execution location (locally or remotely), (ii) the number of packets to be executed and (iii) the corresponding transmission power. This policy offers a dramatic increase in the number of executed packets and a significant energy saving