IEEE 802.15.4 is a standard defined for wireless sensor network applications with limited power and relaxed throughput needs. The devices transmit data during two periods: the contention access period (CAP), during which they can access the channel using CSMA/CA, and the contention free period (CFP), which consists of guaranteed time slots (GTS) allocated to individual devices by the network coordinator. These slots are used by devices for cyclic data transmission. The coordinator can allocate GTS to a maximum of only seven devices, so inefficient utilization of GTS can lead to significant wastage of bandwidth. In this work, we have proposed two algorithms for efficient GTS allocation. The first algorithm is focused on improving the bandwidth utilization of devices, while the second algorithm uses traffic arrival information to allow sharing of GTS slots among more than seven devices. The proposed schemes were tested through simulations; the results show that the new GTS allocation schemes perform better than the original IEEE 802.15.4 standard.

Committee
Dr. Anu Bourgeois (chair)
Dr. Xiaojun Cao
Dr. Yingshu Li