Agile Multi-PHY Wireless Networking
Mina Rady · HAL (Le Centre pour la Communication Scientifique Directe) · 2021
This thesis contributes to the emerging field of agile multi-PHY wireless networking. Industrial wireless networks have relied on a single physical layer for their operation. One example is the standardized IETF 6TiSCH protocol stack for industrial wireless networking, which uses IEEE~802.15.4 O-QPSK radio in the 2.4~GHz band as its physical layer. Advances in radio chip manufacturing have resulted in chips that support a diverse set of long range and short range PHYs. We use the term "PHY'' to refer to any combination of: modulation, frequency band, and coding scheme. In this research, we argue that combining long-range and short-range PHYs can offer balanced network end-to-end performance that no single PHY achieves. We demonstrate how a set of short-range and long-range PHYs can be integrated under one generalized 6TiSCH ("g6TiSCH'') architecture and we evaluate its performance experimentally in a testbed of 36~motes at Inria-Paris. We further demonstrate, experimentally, how a TSCH slotframe can adapt the slot duration on a slot-by-slot basis, as a function of the bitrate of the used PHY ("6DYN''). Finally, we design and evaluate, through simulation, an objective function for RPL that optimizes for network lifetime ("Life-OF''). We demonstrate how Life-OF combines diverse PHYs to boost network lifetime to be up to 470% compared to the IETF standard MRHOF.