TSCH Multiple Slotframe Scheduling for Ensuring Timeliness in TS-SWIPT-Enabled IoT Networks

This paper presents a time-slotted channel hopping (TSCH) multiple slotframe scheduling (TMSS) protocol to ensure the timeliness of energy harvesting and data transmission for sensor devices with different transmission periods in Internet of Things (IoT) networks enabled with time-switching simultaneous wireless information and power transfer (TS-SWIPT). The TMSS uses a modified three-step 6P transaction to allocate power and data cells within the slotframe. The sensor device sets the slotframe length equal to the transmission period and estimates the number of power and data cells for allocation in the configured slotframe and requests cell allocation to the hybrid access point (HAP). Upon request from a sensor device, the HAP executes a cell-overlapping prevention (COP) algorithm to resolve the cell-overlapping problem and responds to the sensor device with a candidate cell list. Upon receiving the response from HAP, the sensor device determines its power and data cells by referring to the cell list. We conducted experimental simulations and compared the TMSS performance to that of the legacy TSCH medium access control (MAC) with a single slotframe and the harvest-then-transmit-based modified enhanced distributed coordination function (EDCF) MAC protocol (HE-MAC). The results showed that TMSS outperforms legacy TSCH MAC and HE-MAC in terms of delay, effective throughput and energy utilization.