  LoRa is a popular wireless technology that enables low-throughput (bytes)
long-range communication (km) at low energy consumption (mW). Its transmission,
though, is on one side prone to interference during long on-air times, and on
the other side subject to duty cycle restrictions. LoRaWAN defines a MAC and a
vertical stack on top of LoRa. LoRaWAN circumvents the above limitations by
imposing a centralized network architecture, which heavily reduces downlink
capacity and prevents peer-to-peer communication. This makes it unusable for
many deployments. The Deterministic and Synchronous Multichannel Extension
(DSME) of IEEE 802.15.4e benefits of time-slotted communication and
peer-to-peer communication and has the potential to overcome LoRaWAN
limitations. In this work, we implement DSME on top of LoRa in the open source
IoT OS RIOT and open the field for first evaluation experiments on real
hardware. Initial results indicate that DSME-LoRa not only enables reliable
peer-to-peer communication for constrained IoT devices, but also scales with an
increasing number of nodes.
