Title
Multi-Hop LoRa Networks Enabled by Concurrent Transmission.
Abstract
In this paper, we strive to construct an efficient multi-hop network based on the sub-GHz low power wide-area technology. Specifically, we investigate the combination of LoRa, a physical-layer standard that can provide several-kilometer outdoor coverage, and concurrent transmission (CT), a recently proposed multi-hop protocol that can significantly improve the network efficiency. The main contributions of this paper are threefold. 1) Since the CT enhances the network efficiency by allowing synchronized packet collisions, the performance of the physical-layer receiver under such packet collisions needs to be carefully examined to ensure the network reliability. We first extensively evaluate the LoRa receiver performance under CT to verify that LoRa is compatible to CT. Specifically, we find that, due to the time-domain and frequency domain energy spreading effect, LoRa is robust to the packet collisions resulting from CT. 2) We further find the receiver performance under CT can be further improved by introducing timing offsets between the relaying packets. In view of this, we propose a timing delay insertion method, the offset-CT method, that adds random timing delay before the packets while preventing the timing offset from diverging over the multi-hop network. 3) We conduct proof-of-concept experiments to demonstrate the feasibility of CT-based LoRa multi-hop network and the performance improvement brought by the proposed offset-CT method.
Year
DOI
Venue
2017
10.1109/ACCESS.2017.2755858
IEEE ACCESS
Keywords
Field
DocType
LoRa,concurrent transmission,multi-hop networks,mesh networks,communication networks,relay networks,ad hoc networks
Computer science,Frequency-shift keying,Network packet,Computer network,Real-time computing,Chirp,Reliability (computer networking),Hop (networking),Offset (computer science),Spread spectrum,Performance improvement
Journal
Volume
ISSN
Citations 
5
2169-3536
3
PageRank 
References 
Authors
0.51
11
5
Name
Order
Citations
PageRank
Chun-Hao Liao17710.39
Guibing Zhu251.48
Daiki Kuwabara330.51
Makoto Suzuki46714.19
Hiroyuki Morikawa542.22