  As elderly population increases, portion of dementia patients becomes larger.
Thus social cost of caring dementia patients has been a major concern to many
nations. This article introduces a dementia assistive system operated by
various sensors and devices installed in body area and activity area of
patients. Since this system is served based on a network which includes a
number of nodes, it requires techniques to reduce the network performance
degradation caused by densely composed sensors and devices. This article
introduces existing protocols for communications of sensors and devices at both
low rate and high rate transmission.
