Mixed Delay Constraints in Wyner's Soft-Handoff Network

Wyner's soft-handoff network with mixed delay constraints is considered when neighbouring receivers can cooperate over rate-limited links. Each source message is a combination of independent "fast" and "slow" bits, where the former are subject to a stringent decoding delay. Inner and outer bounds on the capacity region are derived, and the multiplexing gain region is characterized when only transmitters or only receivers cooperate

Mixed Delay Constraints at Maximum Sum-Multiplexing Gain

International audienceCoding schemes are proposed for Wyner's soft-handoff model and for the sectorized hexagonal model when some of the messages are delay-sensitive and cannot profit from transmitter or receiver cooperation. For the soft-handoff network we also provide a converse. It matches the multiplexing-gain achieved by our scheme when the multiplexing gain of the delay-sensitive messages is low or moderate or when the cooperation links have high capacities. In these cases, the sum-multiplexing gain is the same as if only delay-tolerant messages (which can profit from cooperation) were sent. A similar conclusion holds for the sectorized hexagonal model, when the capacities of the cooperation links are large

Joint Channel Coding of Consecutive Messages with Heterogeneous Decoding Deadlines in the Finite Blocklength Regime

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 paper, we study channel coding in this setting by jointly encoding messages as they arrive while decoding the messages separately, allowing for heterogeneous decoding deadlines. For a scheme based on power sharing, we analyze the probability of error in the finite blocklength regime. We show that significant performance improvements can be obtained for short packets by using our scheme instead of standard approaches based on time sharing.Une hypothèse standard dans la conception de systèmes de communication ultra-fiables et de latence ultra-faible est que la durée entre les arrivées de messages est plus grande que le nombre d'utilisations de canaux avant la date limite de décodage. Néanmoins, cette hypothèse échoue lorsque les messages arrivent rapidement et que les contraintes de fiabilité nécessitent que le nombre d'utilisations du canal dépasse le temps entre les arrivées. Dans cet article, nous étudions le codage de canal dans ce contexte en codant conjointement les messages à mesure qu'ils arrivent tout en décodant les messages séparément, ce qui permet des délais de décodage hétérogènes. Pour un schéma basé sur le partage de puissance, nous analysons la probabilité d'erreur dans le régime de longueur de bloc finie. Nous montrons que des améliorations significatives des performances peuvent être obtenues pour les paquets courts en utilisant notre schéma au lieu d'approches standard basées sur le partage du temps

Dirty Paper Coding for Consecutive Messages with Heterogeneous Decoding Deadlines in the Finite Blocklength Regime

To improve reliability in latency-critical applications, a point-to-point communication system with heterogeneous decoding deadlines is considered. Unlike existing work, this system allows for a message to arrive before the decoding deadline of a prior message. A new coding scheme with finite blocklength codewords is introduced exploiting the dirty paper coding principle. Rigorous bounds are derived for achievable error probabilities. Moreover, numerical results illustrate that the proposed scheme outperforms time sharing for a wide range of blocklengths

Joint Channel Coding of Consecutive Messages with Heterogeneous Decoding Deadlines in the Finite Blocklength Regime

International audienceA 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 paper, we study channel coding in this setting by jointly encoding messages as they arrive while decoding the messages separately, allowing for heterogeneous decoding deadlines. For a scheme based on power sharing, we analyze the probability of error in the finite blocklength regime. We show that significant performance improvements can be obtained for short packets by using our scheme instead of standard approaches based on time sharing

Derandomizing Codes for the Binary Adversarial Wiretap Channel of Type II

We revisit the binary adversarial wiretap channel (AWTC) of type II in which an active adversary can read a fraction $r$ and flip a fraction $p$ of codeword bits. The semantic-secrecy capacity of the AWTC II is partially known, where the best-known lower bound is non-constructive, proven via a random coding argument that uses a large number (that is exponential in blocklength $n$) of random bits to seed the random code. In this paper, we establish a new derandomization result in which we match the best-known lower bound of $1-H_2(p)-r$ where $H_2(\cdot)$ is the binary entropy function via a random code that uses a small seed of only $O(n^2)$ bits. Our random code construction is a novel application of pseudolinear codes -- a class of non-linear codes that have $k$-wise independent codewords when picked at random where $k$ is a design parameter. As the key technical tool in our analysis, we provide a soft-covering lemma in the flavor of Goldfeld, Cuff and Permuter (Trans. Inf. Theory 2016) that holds for random codes with $k$-wise independent codewords

Réseaux avec contraintes de latence mixtes

Modern wireless communication networks have to accommodate different types of data traffic with different latency constraints. In particular, delay-sensitive video-applications represent an increasing portion of data traffic. Modern networks also have to accommodate high total data rates, which they can accomplish for example with cooperating terminals or with helper relays such as drones. However, cooperation typically introduces additional communication delays, and is thus not applicable to delay-sensitive data traffic.This thesis focuses on interference networks with mixed-delay constraints and on system architectures where neighbouring transmitters and/or neighbouring receivers can cooperate. In such systems, delay-sensitive messages have to be encoded and decoded without further delay and thus cannot benefit from available cooperation links.We propose various coding schemes that can simultaneously accommodate the transmission of both delay-sensitive and delay-tolerant messages. For the proposed schemes we analyze the multiplexing gains (MG) they achieve over Wyner's soft hand-off network, Wyner's symmetric network, the hexagonal network and the sectorized hexagonal network. For Wyner's soft hand-off network and Wyner's symmetric network, we also provide tight information-theoretic converse results and thus establish the exact set of MG pairs that can simultaneously be achieved for delay-sensitive and delay-tolerant data. These results demonstrate that when both transmitters and receivers cooperate and the cooperation rates are sufficiently large, it is possible to achieve the largest MG for delay-sensitive messages without penalizing the maximum sum MG of both delay-sensitive and delay-tolerant messages. In contrast, under our proposed schemes, the sending of delay-sensitive data in hexagonal models decreases the maximum sum MG. This penalty vanishes when we consider the sectorized hexagonal network where each cell is divided into three non-interfering sectors by employing directional antennas at the base stations.We further propose similar coding schemes for scenarios with different types of random user activity. We specifically consider two setups. In the first setup, each active transmitter always has delay-tolerant data to send and delay-sensitive data arrival is random. In the second setup, both delay-tolerant and delay-sensitive data arrivals are random. The obtained MG regions show that in the first setup, increasing the delay-sensitive MG always decreases the sum MG. In contrast, in the second setup, for certain parameters, the highest sum MG is achieved at maximum delay-sensitive MG and thus increasing the delay-sensitive MG provides a gain in sum MG.Additionally, we also study a cloud radio access network with mixed delay constraints, i.e., where each mobile user can simultaneously send a delay-sensitive and a delay-tolerant stream and only the delay-tolerant data is jointly decoded at the cloud unit. For this network, we derive inner and outer bounds on the capacity region under mixed delay constraints, and we exactly characterize the optimal MG region. At high signal-to-noise ratio (SNR), our results show that for moderate fronthaul capacities, the maximum MG for delay-sensitive messages remains unchanged over a large regime of small and moderate MGs of delay-sensitive messages. The sum MG is thus improved if some of the messages can directly be decoded at the base stations. At moderate SNR, the results show that when the data rate of delay-sensitive messages is small or moderate, the achievable sum rate is constant.Les réseaux de communication sans fil modernes doivent s'adapter à différents types de trafic de données avec des contraintes de latence différentes. Les applications vidéo sensibles à la latence, en particulier, représentent une part croissante du trafic de données. En outre, les réseaux modernes doivent accepter des débits de données élevés, ce qu'ils peuvent faire par exemple avec des terminaux coopératifs ou avec l'assistance de relais tels que les drones. Cependant, la coopération introduit généralement des retards de communication supplémentaires et n'est donc pas applicable au trafic de données sensibles à la latence.Cette thèse porte sur les réseaux d'interférence avec des contraintes de latence mixtes et sur les architectures de systèmes où des émetteurs et/ou des récepteurs voisins peuvent coopérer. Dans de tels systèmes, les messages sensibles à la latence doivent être encodés et décodés sans délai et ainsi ne peuvent pas bénéficier des liens de coopération disponibles. Nous proposons différents schémas de codage pour permettre la transmission simultanée de messages sensibles et insensibles à la latence. Pour les schémas proposés, nous analysons les gains de multiplexage (MG) qu'ils réalisent sur le réseau de transfert intercellulaire souple de Wyner, le réseau symétrique de Wyner, le réseau hexagonal et le réseau hexagonal sectorisé. Pour le réseau de transfert souple de Wyner et le réseau symétrique de Wyner, nous identifions aussi des résultats étroits s'agissant de leurs limites en théorie de l'information et nous définissons ainsi l'ensemble exact de paires MG qui peuvent être obtenus simultanément pour les données sensibles et insensibles à la latence. Ces résultats montrent que lorsque les émetteurs et les récepteurs peuvent coopérer et que les taux de coopération sont suffisamment élevés, il est possible d'obtenir le plus grand MG possible pour les messages sensibles à la latence sans pénaliser la somme maximale des MG pour l'ensemble des messages sensibles et insensibles à la latence. Cependant, la somme des MG des systèmes que nous proposons pour le modèle hexagonal est diminuée en présence de données sensibles à la latence. Cette pénalité disparaît dans le cas du réseau hexagonal sectorisé quand chaque cellule est divisée en trois secteurs non interférents en équipant les stations de base d'antennes directionnelles.Nous proposons, de surcroît, des schémas de codage similaires en fonction de différents types d'activité aléatoire de la part des usagers du réseau. Nous considérons plus particulièrement deux configurations. Dans la première configuration, l'augmentation du taux de MG correspondant aux données sensibles à la latence diminue toujours la somme des MG. En revanche, dans la seconde configuration, pour certains paramètres, la plus grande somme des MG est obtenue au maximum du taux de MG correspondant aux données sensibles à la latence et donc l'augmentation des MG sensibles à la latence améliore la somme des MG.Nous étudions aussi un réseau d'accès radio "cloud" avec des contraintes de latence mixtes, c'est-à-dire où chaque utilisateur mobile peut simultanément envoyer un flux sensible à la latence et un flux qui la tolère et où seules les données sensibles sont décodées conjointement au sein du cloud. Pour ce réseau, nous dérivons les limites intérieures et extérieures de la région de capacité sous des contraintes de latence mixtes, et nous caractérisons précisément la région MG optimale. Lorsque le rapport signal/bruit (SNR) est élevé, nos résultats démontrent que, pour des capacités frontales modérées, le MG maximal pour les messages sensibles à la latence reste inchangé sur une large gamme de petits et moyens MG de messages sensibles à la latence. Pour un SNR modéré, les résultats montrent que lorsque le débit de messages sensibles à la latence est faible ou modéré, nous obtenons une somme de débit de données constante

The Effect of Acute Ethanol and Gabapentin Administration on Spatial Learning and Memory

 Introduction: Patients with epilepsy can have impaired cognitive abilities. Many factors contribute to this impairment, including the adverse effects of antiepileptic drugs like Gabapentin (GBP). Apart from anti-epilectic action, Gabapentin is used to relieve ethanol withdrawal syndrome. Because both GBP and ethanol act on GABA ergic system, the purpose of this study was to evaluate their effect and interaction on spatial learning and memory. Material and Methods: Male Sprague-Dawley rats were trained in the Morris water maze for 5 consecutive days. On the sixth day, a probe test was performed to assess the retention phase or spatial rats’ memory ability. Ethanol (1.5 g/kg i.p.) and GBP (30 mg/kg i.p.) was administered each day 30 and 40 minutes before testing respectively. Results: Acute ethanol administration selectively impaired spatial memory (p<0.05), yet it failed to impair the acquisition phase (learning). Contradictorily GBP selectively impaired learning on second and forth days. Conclusion: These findings demonstrate that GBP and acute ethanol impair different phases of learning probably by modifying different neuronal pathways in cognitive areas of the brain

Multiplexing Gain Region of Sectorized Cellular Networks with Mixed Delay Constraints

International audienceThe sectorized hexagonal model with mixed delay constraints is considered when both neighbouring mobile users and base stations can cooperate over rate-limited links. Each message is a combination of independent "fast" and "slow" bits, where the former are subject to a stringent delay constraint and cannot profit from cooperation. Inner and outer bounds on the multiplexing gain region are derived. The obtained results show that for small cooperation prelogs or moderate "fast" multiplexing gains, the overall performance (sum multiplexing gain) is hardly decreased by the stringent delay constraints on the "fast" bits. For large cooperation prelogs and large "fast" multiplexing gains, increasing the "fast" multiplexing gain by ∆ comes at the expense of decreasing the sum multiplexing gain by 3∆