Itron Networked Solutions, Inc.

Kamal Poorrezaei

Paul Dietrich

Brandon Inberg

A battery powered node within a wireless mesh network maintains a mapping between temperature and oscillator drift and compensates for oscillator drift based on this mapping. When the mapping includes insufficient data points to map the current temperature to an oscillator drift value, the battery powered node requests calibration packets from an adjacent upstream node in the network. The adjacent node transmits two calibration packets with a transmit time delta and also indicates this time delta in the first calibration packet. The battery powered node receives the two calibration packets and measures the receive time delta. The battery powered node compares the transmit time delta to the receive time delta to determine oscillator drift compared to an oscillator in the adjacent node. The battery powered node then updates the mapping based on the current temperature and determined oscillator drift.

Compensating for oscillator drift in wireless mesh networks

A battery-powered node within a wireless mesh network performs energy-aware packet routing based on multiple factors. The battery powered node computes, for a given link to an adjacent node, the energy needed to transmit a packet to the adjacent node. The battery-powered node also determines the amount of battery energy remaining in the adjacent node. Based on these two factors, the battery powered node computes a link cost associated with the link to the adjacent node. The battery-powered node performs a similar computation for all adjacent nodes and then forwards packets via these adjacent nodes based on the associated link costs. The battery-powered node also maintains a table of routes through adjacent nodes, and reroutes packets through different adjacent nodes in response to link failures.

Energy aware routing for mesh networks

A wireless mesh network includes a mesh of continuously-powered devices (CPDs) and a mesh of battery-powered devices (BPDs). The BPDs are organized into hop layers based on hopping distance to the mesh of CPDs. The CPDs transmit time beacons to BPDs in a first hop layer during a first receive window associated with the first hop layer. The BPDs in the first hop layer then transmit time beacons to BPDs in a second hop layer during a second receive window. In this manner, the wireless mesh network propagates time values throughout the BPD mesh. Based on these time values, the BPDs power on during short time intervals to exchange data with neighboring BPDs, and then power off for longer time intervals, thereby conserving battery power. The techniques described herein for conserving battery power for BPDs may also be applied to conserve power consumption of CPDs.

Time distribution scheme for wireless mesh networks

A wireless mesh network includes a mesh of continuously-powered devices (CPDs) and a mesh of battery-powered devices (BPDs). The BPDs are organized into hop layers based on hopping distance to the mesh of CPDs. In a medium latency communication mode, a given BPD receives data during a receive window that is scheduled to occur within either the first half of a communication window or the second half of the communication window, depending on the parity of the hop layer where the BPD resides. With this approach, a data packet can traverse one hop of the BPD mesh per communication window. In a low-latency communication mode, a given BPD receives and transmits data according to an alternating pattern that depends on the parity of the hop layer where the node resides. With this technique, a data packet can traverse multiple hops of the BPD mesh within a single communication window. These techniques also are applicable to CPDs and other types of nodes as well.

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San Jose, CA, United States of America

Kamal Poorrezaei