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Inscriptions closes à cette réunion.
19 personnes membres du GdR ISIS, et 11 personnes non membres du GdR, sont inscrits à cette réunion.
Capacité de la salle : 100 personnes.
De plus, une diffusion en vidéoconférence de la journée sera disponible.
Date : 24 novembre de 10h à 17h30
L'objectif de cette journée est de faire le point sur les avancées récentes dans le domaine de la transmission de paquets courts pour les réseaux sans fils. Différentes thématiques seront abordées : les limites théoriques, la forme d'onde et les codes correcteurs d'erreurs associés, les problèmes de réception et de gestion des collisions et les problèmes d'allocation de ressources. Notre objectif est de réunir académiques et industriels pour échanger autour de cette thématique afin de faire émerger les problèmes encore ouverts et les techniques les plus prometteuses pour la transmission des paquets de faible taille.
Lien de connexion Teams: GdR ISIS Workhop
9h30-10h : Accueil Café,
10h-10h10 : Introduction de la journée
10h10-10h50 : Guiseppe Durisi (Chalmers University of Technology) : Finite-blocklength bounds for fading channels.
10h50-11h10 : Homa Nikbakht (INRIA) : Joint channel coding of consecutive messages with heterogeneous decoding deadlines in the finite blocklength regime.
11h10-11h50 : Gianluigi Liva (DLR Munich) : List decoding of short codes over fading channels.
11h50-12h05: Pause Café.
12h05-12h25 : Samet Gelincik (INSA Rennes) : Achieving PAC Code Performance with SCL Decoding without Extra Computational Complexity
12h25-12h45 : Joachim Rosseel (CEA-LETI/ETIS) : Error structure aware parallel BP-RNN decoders for short LDPC codes.
12h45-14h15: Repas libre à l'extérieur.
14h15-14h55 : Petar Popovski (Aalborg University) : How to identify and authenticate users in massive unsourced random access?
14h55-15h35 : Mustafa Coskun (TU Munich) : Polar codes for communication over unknown fading channels.
16h10-16h50 : Maxime Guillaud (Huawei Paris) : Waveforms for random access in fading channels.
16h50-17h10 : Nouman Bashir (Université Sorbonne Paris Nord) : A collision avoiding packet scheduling and energy-efficient routing technique for wireless sensor networks.
17h10-17h30 : Lina Mroueh (ISEP): Adaptive multi-channels allocation in LoRa networks.
17h30 : Fin de la journée.
10h10 - 10h50, Giuseppe Durisi (Chalmers University)
Title: "Short packets over wireless fading networks"
Abstract: To support the Internet-of-Things vision of enabling distributed autonomous systems operating in real time, we need a new wireless infrastructure, able to provide highly reliable and low-latency connectivity to a large number of sporadically active devices transmitting short data packets. In this talk, I will illustrate how to use recent results in finite-blocklength information theory to optimally design such a wireless infrastructure. Scenarios that are relevant for 5G and beyond will be presented. In particular, I will discuss how to support low-latency, ultra-reliable communications in both cellular and cell-free massive multiple-input multiple-output architectures.
11h10 - 11h50, Gianluigi Liva (DLR Munich)
Title: "List decoding of short codes over fading channels"
14h15-14h55, Petar Popovski (Aalborg University)
Title: "How to Identify and Authenticate Users in Massive Unsourced Random Access?"
Abstract: Identification and authentication are two essential features for traditional random access protocols. In ALOHA-based random access, the packets usually include a field with a unique user address. However, when the number of users is massive and relatively small packets are transmitted, the overhead of including such field becomes restrictive. In unsourced random access (U-RA), the packets do not include any address field for the user, which maximizes the number of useful bits that are transmitted. However, by definition an U-RA protocol does not provide user identification. This talk presents a scheme that builds upon an underlying U-RA protocol and solves the problem of user identification and authentication. In the presented scheme, the users generate a message authentication code (MAC) that provides these functionalities without violating the main principle of unsourced random access: the selection of codewords from a common codebook is i.i.d. among all users.
14h55 - 15h35, Mustafa Coskun (TU Munich)
Title: "Polar codes for communication over unknown fading channels"
Abstract: A polar-coded transmission scheme with joint channel estimation and decoding is proposed for channels with unknown channel state information (CSI). The CSI is estimated via successive cancellation list decoding and the constraints imposed by the frozen bits. Simulations with 5G polar codes and QPSK show gains of up to 2 dB at a frame error rate (FER) of 1e?4 over classical pilot-assisted transmission for various non-coherent models.
16h10 - 16h50, Maxime Guillaud (Huawei Paris)
Title: "Waveforms for random access in fading channels"
Abstract:I will discuss modulation and waveform design for short-packet transmission over fading channels. In the short-packet regime, the classical assumption that CSI is available or can be acquired with negligible overhead does not hold. I will thus focus on the design of non-coherent modulations for the block-fading channel. For the single-user case, this classically gives rise to Grassmannian modulations. In the multi-user case, I will analyze the problem of efficient vector codebook design as an optimization problem, and describe some simple criteria that allow to provide good approximate solutions to the codebook design question. Finally, I will address the problem of modulation design for short packet random access, and present a modulation that allows practical multi-packet reception with randomly activated users over fading channels, thus alleviating the problem of packet collisions.
10h50 - 11h10 : Homa Nikbakht (INRIA)
Title: "Joint channel coding of consecutive messages with heterogeneous decoding deadlines in the finite blocklength regime"
Abstract: One of the pillars of 5G is ultra-reliable low latency communications (URLLC), where the goal is to transmit typically small quantities of data with a very low probability of error and strict decoding deadlines. With applications ranging from autonomous driving to remote surgery, a number of channel coding schemes have been proposed including short LDPC and polar codes. A standard assumption in the design of ultra-reliable low-latency communication systems is that the duration between message arrivals is larger than the number of channel uses before the decoding deadline. Nevertheless, this assumption fails when messages rapidly arrive and reliability constraints require that the number of channel uses exceeds the time between arrivals. In this talk, we study channel coding in this setting by jointly encoding messages as they arrive while decoding the messages separately, allowing for heterogeneous decoding deadlines.
12h05 - 12h25, Samet Gelincik (INSA Rennes)
Title: "Achieving PAC Code Performance with SCL Decoding without Extra Computational Complexity"
Abstract: The minimum distance and the number of low weight codewords are essential to obtain good performance with successive cancellation list decoding of finite blocklength polar codes at moderate and high list sizes. In this paper, we propose a method to decrease the number of low weight codewords for some information lengths with a very low computational complexity. In the proposed method, some information bits are encoded by several rows of the polar encoding matrix, i.e., each of the dynamic frozen bits is chosen the same as one of the preceding information bits. The dynamic frozen bit index set is determined by using the connection between the binary representation of the row indices and the number of common 1-bit positions of any given rows. The resulting design is shown to perform as well as polarization-adjusted-convolutional codes under successive cancellation list decoding but with significant computational complexity savings. These findings pave the way for the use of polar codes in applications with stringent complexity and with low energy consumption constraints.
12h25 - 12h45, Joachim Rosseel (CEA-LETI / ETIS)
Title: "Error structure aware parallel BP-RNN decoders for short LDPC codes"
Abstract: This article deals with the decoding of short block length Low Density Parity Check (LDPC) codes. It has already been demonstrated that Belief Propagation (BP) can be adjusted to the short coding length, thanks to its modeling by a Recurrent Neural Network (BP-RNN). To strengthen this adaptation, we introduce a new training method for the BP-RNN. Its aim is to specialize the BP-RNN on error events sharing the same structural properties. This approach is then associated with a new decoder composed of several parallel specialized BP-RNN decoders, each trained on correcting a different type of error events. Our results show that the proposed specialized BP-RNNs working in parallel effectively enhance the decoding capacity for short block length LDPC codes.
16h50 - 17h10, Nouman Bashir (Université Sorbonne Paris Nord)
Title: "A Collision Avoiding Packet Scheduling and Energy-Efficient Routing Technique for Wireless Sensor Networks"
Abstract: This work proposes a cross-layer solution to reduce overhead and packets collisions occurring in wireless networks. We cannot eliminate collisions even with a collision avoidance mechanism in CSMA that results in increased latency and network resources wastage due to retransmissions. This work does not use RTS/CTS signals and introduces a scheduling interval that avoids collisions among the packets arising from the same source. This scheduling interval also takes care of hidden node issues in wireless networks. The absence of CTS/RTS signals reduces communication overhead, and also no retransmissions results in reduced latency.
17h10 - 17h30, Lina Mroueh (ISEP)
Title: "Adaptive Multi-Channels Allocation in LoRa Networks"
Abstract: Adaptive Multi-Channels Allocation in LoRa Networks : To avoid the near-far problem in LoRa networks, we propose an adaptive multi-channel allocation. This policy spreads the chirps, depending on the distance, progressively onto one, two or four adjacent channels of 125 kHz each, while keeping the same power consumption and data rate. This strategy enhances the variation with distance of the coverage probability compared to a single-channel allocation.
Date : 2021-11-24
Lieu : ISEP, salle L012, 10 rue de Vanves, 92130 Issy Les Moulineaux (métro ligne 12, station Corentin Celton) + connexion Teams
Thèmes scientifiques :
D - Télécommunications : compression, protection, transmission
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(c) GdR 720 ISIS - CNRS - 2011-2022.