  Recent applications in large-scale wireless mesh networks (WSN), e.g.,
Advanced Metering Infrastructure (AMI) scenarios, expect to support an extended
number of nodes with higher throughput, which cannot be sufficiently supported
by the current WSN protocols. Two prior protocols, Wi-SUN Field Area Network
(Wi-SUN FAN) and IETF 6TiSCH standards, are popularly used that are
respectively based on asynchronous Carrier Sense Multiple Access / Collision
Avoidance (CSMA/CA) and IEEE 802.15.4 Time Scheduled Channel Hopping (TSCH).
However, the former one with CSMA/CA can be prone to the Hidden Node Problem
(HNP) that leads to a degradation of reliability, while the latter one with
TSCH avoids HNP by using synchronously scheduling but requires massive control
signalling that degrades the upper-bound of throughput. Accordingly, this paper
tackles the challenge of how to improve the upper-bound of throughput without
loss of reliability. To do so, we first present an in-depth evaluation of
reliability and throughput between the two existing standards via system-level
simulation. We then propose a self-configurable grouping (SCG) method to
cluster nodes without using location information of each node. This SCG method
eliminates around 99\% HNP in CSMA/CA, thus greatly improves its reliability
with maintaining the relatively high upper-bound of throughput. Our results
show that the SCG method almost doubles the network throughput compared with
both 6TiSCH and Wi-SUN FAN in heavy traffic scenarios, while providing
extremely high reliability of more than 99.999\%.
