6533b834fe1ef96bd129d855
RESEARCH PRODUCT
Impact of LoRa Imperfect Orthogonality: Analysis of Link-Level Performance
Giuseppe SantaromitaStefano MangioneDaniele CroceIlenia TinnirelloMichele Gucciardosubject
LoRa spreading factor interferenceSettore ING-INF/03 - TelecomunicazioniNetwork packetComputer sciencebusiness.industry010401 analytical chemistryinterference020206 networking & telecommunications02 engineering and technologyLoRa01 natural sciences0104 chemical sciencesComputer Science ApplicationsPacket lossModulationModeling and Simulation0202 electrical engineering electronic engineering information engineeringChirpspreading factorLink levelImperfectElectrical and Electronic EngineeringbusinessComputer networkdescription
In this letter, we focus on the evaluation of link-level performance of LoRa technology, in the usual network scenario with a central gateway and high-density deployment of end-devices. LoRa technology achieves wide coverage areas, low power consumption and robustness to interference thanks to a chirp spread-spectrum modulation, in which chirps modulated with different spreading factors (SFs) are quasi-orthogonal. We focus on the performance analysis of a single receiver in presence of collisions. First, we analyze LoRa modulation numerically and show that collisions between packets modulated with different SFs can indeed cause packet loss if the interference power received is strong enough. Second, we validate such findings in experiments based on commercial devices and software-defined radios. Contradicting the common belief that SFs can be considered orthogonal, our results demonstrate that inter-SF collisions are indeed an issue in LoRa networks and, thus, allocating higher SFs to users far from the gateway might not necessarily improve their link capacity, in case of congested networks.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-01-01 | IEEE Communications Letters |