  With the ubiquitous sensing enabled by wireless sensor network technologies,
Internet of Things (IoT) is developed to many areas of modern day living. The
inexpensive IoT devices and platforms capable of wireless communications enable
the ability to measure, infer and understand environmental indicators, from
delicate ecologies and natural resources to urban environments. In this paper,
we firstly investigate a scalable multimode-based MAC protocol, IoT-MAC, which
consists of a channel contention period and a data transmission period, to
reduce contention of channel access due to coexist of many IoT devices.
Secondly, we study a data transmission scheduling algorithm to maximise data
collection under the constraints of radio link quality and remaining energy of
the IoT node, while ensuring a fair access to the radio channel. To study the
performance of data reception rate, packet loss rate and latency, we evaluate
the IoT-MAC and scheduling algorithm with varying data rate and different
network scale.
