Analysis of buffer size dimensioning in GTS enabled IEEE 802.15.4 WSN for real-time applications

This paper explores the problem of bandwidth under utilisation in WSN, and evaluates the guaranteed time slot (GTS) mechanism performance using OPNET ^™. Time-critical applications for WSNs are an important class of services supported by the IEEE 802.15.4 standard. The IEEE 802.15.4 standard grants exclusive use of a wireless channel for time-critical traffic through GTS medium access control (MAC) mechanism. The GTS is activated in the beacon-enabled mode based on the superframe structure. A node has to use at least one whole GTS in a transmission. However, each node may not fully utilise its transmission capacity in a particular time slot if the packet arrival rate is too small. Hence, bandwidth utilisation is reduced. Queue management and buffer dimensioning at the nodes becomes an important factor to quantify the optimal parameters to tune the network for a better performance without making any modifications to the existing protocol.