The IEEE 802.15.4 standard offers a flexible communication solution for low-rate
wireless small area networks. When the beacon mode is enabled, real-time communication is
possible by using the Guaranteed Time Slots (GTS) mechanism. However, the beacon-enabled
mode only supports a maximum of seven GTS allocated in each superframe, preventing other
nodes to benefit from the guaranteed service. This paper introduces the SIGHT (Skips In GTS
scHeduling for IEEE 802.15.4 neTworks) model, which incorporates a dynamic GTS allocation
policy for IEEE 802.15.4 networks based on the (m,k)-firm task model. Our approach ensures
that at least m messages are allocated in a guaranteed slot, for any k consecutive superframes.
It adopts a deterministic schedulability test and an on-line prioritization heuristic algorithm
called Slotted DBP (Distance Based Priority) to attend requests according to this schedulability
model. A simulation model has been developed, in order to compare the behaviour in overload
conditions of the proposed Slotted DBP with other approaches (DWCS and FIFO).
Tipo (Avaliação Docente):
Nº de páginas: