A New Phase Transition for Local Delays in MANETs - Inria - Institut national de recherche en sciences et technologies du numérique Accéder directement au contenu
Communication Dans Un Congrès Année : 2010

A New Phase Transition for Local Delays in MANETs

Résumé

We consider Mobile Ad-hoc Network (MANET) with transmitters located according to a Poisson point in the Euclidean plane, slotted Aloha Medium Access (MAC) protocol and the so-called outage scenario, where a successful transmission requires a Signal-to-Interference-and-Noise (SINR) larger than some threshold. We analyze the local delays in such a network, namely the number of times slots required for nodes to transmit a packet to their prescribed next-hop receivers. The analysis depends very much on the receiver scenario and on the variability of the fading. In most cases, each node has finite-mean geometric random delay and thus a positive next hop throughput. However, the spatial (or large population) averaging of these individual finite mean-delays leads to infinite values in several practical cases, including the Rayleigh fading and positive thermal noise case. In some cases it exhibits an interesting phase transition phenomenon where the spatial average is finite when certain model parameters are below a threshold and infinite above. We call this phenomenon, contention phase transition. We argue that the spatial average of the mean local delays is infinite primarily because of the outage logic, where one transmits full packets at time slots when the receiver is covered at the required SINR and where one wastes all the other time slots. This results in the "RESTART" mechanism, which in turn explains why we have infinite spatial average. Adaptive coding offers a nice way of breaking the outage/RESTART logic. We show examples where the average delays are finite in the adaptive coding case, whereas they are infinite in the outage case.
Fichier principal
Vignette du fichier
delay6_hyperlinked.pdf (281.79 Ko) Télécharger le fichier
delay6.pdf (186.79 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

inria-00435237 , version 1 (23-11-2009)
inria-00435237 , version 2 (21-12-2009)
inria-00435237 , version 3 (03-02-2010)

Identifiants

Citer

François Baccelli, Bartlomiej Blaszczyszyn. A New Phase Transition for Local Delays in MANETs. Infocom, IEEE, Mar 2010, San Diego, United States. pp.1-9, ⟨10.1109/INFCOM.2010.5462132⟩. ⟨inria-00435237v3⟩
174 Consultations
297 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More