Asymptotic and Finite Frame Length Analysis of Frame Asynchronous Coded Slotted ALOHA
Paper in proceedings, 2016

We consider a frame-asynchronous coded slotted ALOHA (FA-CSA) system where users join according to a Pois- son random process. In contrast to standard frame-synchronous CSA (FS-CSA), when a user joins the system, it transmits a first replica of its message in the following slot and other replicas uniformly at random in a number of subsequent slots. We derive the (approximate) density evolution that characterizes the asymptotic performance of FA-CSA when the frame length goes to infinity. We show that, if the receiver can monitor the system before users start transmitting, a boundary effect similar to that of spatially-coupled codes occurs, which greatly improves the decoding threshold as compared to FS-CSA. We also derive analytical approximations of the error floor (EF) in the finite frame length regime. We show that FA-CSA yields in general lower EF, better performance in the waterfall region, and lower average delay, as compared to FS-CSA.

Author

Erik Sandgren

Chalmers, Signals and Systems, Kommunikationssystem, informationsteori och antenner, Communication Systems

Alexandre Graell i Amat

Chalmers, Signals and Systems, Kommunikationssystem, informationsteori och antenner, Communication Systems

Fredrik Brännström

Chalmers, Signals and Systems, Kommunikationssystem, informationsteori och antenner, Communication Systems

International Symposium on Turbo Codes and Iterative Information Processing, ISTC

21654700 (ISSN) 21654719 (eISSN)

81-85 7593081

Areas of Advance

Information and Communication Technology

Subject Categories

Communication Systems

DOI

10.1109/ISTC.2016.7593081

ISBN

978-1-5090-3401-7

More information

Created

10/8/2017