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Understanding LoRa
15. Understanding LoRa
15.1. Introduction
LoRa is a new, private and spread-spectrum modulation technique which allows sending data at extremely low data-rates
to extremely long ranges. The low data-rate (down to few bytes per second) and LoRa modulation lead to very low receiver
sensitivity (down to -134 dBm), which combined to an output power of +14 dBm means extremely large link budgets: up to
148 dB, what means more than 22 km (13.6 miles) in LOS links and up to 2 km (1.2 miles) in NLOS links in urban environment.
Libelium’s LoRa module works in both 868 and 900 MHz ISM bands, which makes it suitable for virtually any country. Those
frequency bands are lower than the popular 2.4 GHz band, so path loss attenuation is better in LoRa. In addition, 868 and 900
MHz are bands with much fewer interference than the highly populated 2.4 GHz band. Besides, these low frequencies provide
great penetration in possible materials (brick walls, trees, concrete), so these bands get less loss in the presence of obstacles
than higher bands.
The great performance of LoRa in all these 3 features (good sensitivity, low path loss, good obstacle penetration) makes LoRa
a disruptive technology enabling really long range links. This is specially important in urban scenarios, with very difficult
transmission conditions. To sum up, LoRa can get long ranges in Smart Cities deployments, so it reduces dramatically the size of
the backbone network (repeaters, gateways or concentrators).
Figure: Map of the NLOS long range tests in Zaragoza
