Slot Bonding for Adaptive Modulations in IEEE 802.15.4e TSCH Networks

Parent and PHY Selection in Slot Bonding IEEE 802.15.4e TSCH Networks

“…In our previous work, the slot bonding technique was proposed to combine multiple PHYs with various data rates in a single TSCH network. It allows the combining of multiple TSCH time slots of regular length into a bonded slot with a length large enough to transmit or receive a packet using the data rate of the PHY selected for the link [ 7 ]. By adapting the length of the bonded slot as closely as possible to the duration required by the data rate of the selected PHY, slot bonding avoids wasting valuable airtime.…”

“…The authors defined two alternative timeslot structures allowing multiple packet transmissions to increase the throughput for higher data rate PHYs while maintaining a fixed slot duration. This approach is different from the slot bonding, in which only one packet is transmitted, but the slot length is adapted to the chosen PHY [ 7 ]. Additionally, they developed a flexible Link Quality Estimation technique to dynamically switch between PHYs depending on the current propagation characteristics of the link.…”

“…In contrast, as explained earlier, traditional TSCH relies on fixed-duration slots, long enough to send a packet of any size given the fixed data rate, which results in wasted airtime if different PHYs with different data rates are used simultaneously. In our previous work, it was shown that the resource-efficiency of slot bonding results in a better network overall packet delivery ratio [ 7 ]. For more results and a detailed explanation on slot bonding, the reader is referred back to that work.…”

“…In our previous work, a GA was defined that acted as a centralized scheduler for multi-PHY TSCH networks by making parent, PHY and slots selections for each node in the network [ 7 ]. This GA allowed us to implement the slot bonding problem and find solutions in near-optimal fashion.…”

“…Integrating multi-PHY support in a 6TiSCH sensor network therefore implies, on the one hand, dealing with the different transmission lengths and bandwidth requirements to fit the PHY allocation in the TSCH schedule and, on the other hand, defining policies on how to select the appropriate PHY for each network link. In our previous work, the question of how different PHYs can be fitted into a TSCH schedule was answered by introducing the concepts of slot and channel bonding [ 7 ]. The former allows the combination of multiple TSCH time slots of regular length into a larger bonded slot.…”