The trade-offs of cell over-provisioning in IEEE 802.15.4 TSCH networks

Wireless industrial applications require high level of Quality of Service (QoS) such as low-delay and jitter performances, low-power operations as well as end-to-end reliability close to 100%. However, considering the large number of wireless networks operating in 2.4 GHz, the radio technologies are more prone to the external interference, which eventually may negatively affect the reliability, the delay and the goodput performance due to collisions and retransmissions. To tackle the previously detailed issues, Time-Slotted Channel Hopping (TSCH) Medium Access Control (MAC) protocol emerged with IEEE 802.15.4-2015 as an alternative to the industrial standards such as WirelessHART and ISA100.11a. TSCH is based on frequency hopping to avoid the interference, while the medium access is based on a scheduler (i.e., slotframe) that repeats periodically to avoid the collisions. Yet, the majority of the proposed TSCH schedulers are based on traditional collision detection and retransmission in the following slotframe, which essentially increases the end-to-end delay performance. In this poster, we consider allocating consecutive timeslots for a single data transmission, to allow thus, to retransmit the data packet within the slotframe in case of losses. We study the potential trade-offs, reliability and delay versus energy consumption, when considering the over-allocation approach.