An introduction to Sigfox and LoRa PHY and MAC layers
Résumé
In this paper we present an introduction to Sigfox and LoRa physical and MAC Layers. I. SIGFOX MODULATION A. Sigfox Physical layer Sigfox is based on ultra-narrow band (UNB) physical layer where the binary data are broadcast with a differential binary phase shift keying (DBPSK) modulation at a very low rate R b,s = 100 bps. Thus, the transmitted signal occupies a band of approximatively W s = 100Hz. Sigfox nodes use a Random Frequency and Time Division Multiple Access (RFTDMA) to transmit their signals. The frequency hopping is done inside a bandwidth B >> W s. This ensures channel diversity and deep fading protection. The expression for the signal (or packet) transmitted by the Sigfox node n s is: r ns s (t) = k∈Ss A k g(t − kT s)e j2πfpt (1) where • T s = 1 R b,s is the symbol period, • A k is the DBPSK symbol transmitted at time kT s ,
Domaines
Sciences de l'ingénieur [physics]
Origine : Fichiers produits par l'(les) auteur(s)
Loading...