Precise clock distribution in beacon enabled, meshed IEEE 802.15.4/ZigBee networks

The need for high reliability wireless communication has triggered the interest in mesh networks recently. Even though promising in various aspects, IEEE 802.15.4/ZigBee offers very basic meshing capabilities only. The introduction of synchronizing beacons in this mode has been proposed to achieve efficient duty cycle management. However, once the beacon scheduling problem is solved, a need for a tight synchronization and for an algorithm addressing fast timing recovery after long sleep periods still persists. Therefore, this paper introduces a clock recovery algorithm which is closely related to a distributed beacon scheduling and is optimized for a hardware based implementation. The results show the applicability of the approach by extensive simulations even for large networks of several thousand nodes in wireless mesh networks (WMNs) based on IEEE 802.15.4/ZigBee.