Abstract: This invention relates to methods and devices for frequency distribution based on, for example, the IEEE 1588 Precision Time Protocol (PTP). Packet delay variation (PDV) is a direct contributor to the noise in the recovered clock and various techniques have been proposed to mitigate its effects. Embodiments of the invention provide a mechanism to directly measure and remove PDV effects in the clock recovery mechanism at a slave clock. One particular embodiment provides a clock recovery mechanism including a phase-locked loop (PLL) with a PDV compensation feature built-in. An aim of the invention is to enable a slave clock to recover the master clock to a higher quality as if the communication path between master and slave is free of PDV. This technique may allow a packet network to provide clock synchronization services to the same level as time division multiplexing (TDM) networks and Global Positioning System (GPS).

Abstract: This invention relates to methods and devices for frequency distribution based on, for example, the IEEE 1588 Precision Time Protocol (PTP). Packet delay variation (PDV) is a direct contributor to the noise in the recovered clock and various techniques have been proposed to mitigate its effects. Embodiments of the invention provide a mechanism to directly measure and remove PDV effects in the clock recovery mechanism at a slave clock. One particular embodiment provides a clock recovery mechanism including a phase-locked loop (PLL) with a PDV compensation feature built-in. An aim of the invention is to enable a slave clock to recover the master clock to a higher quality as if the communication path between master and slave is free of PDV. This technique may allow a packet network to provide clock synchronization services to the same level as time division multiplexing (TDM) networks and Global Positioning System (GPS).

Abstract: Methods and systems for configuring ad-hoc networks, especially a self-configuring wireless sensor networks, are described. The network has an initial number of anchors with known positions that broadcast a signal. The signals are received by distributed nodes whose position is not yet known. The nodes rank the received signal based on a Quality of Link (QoL; received signal strength) and compute a Quality of position Estimate (QoE) for the node. The node with the best QoE is elevated to anchor. This process gradually increases the number of available anchors in the network and hence the position accuracy for additional nodes. The system can be used for geolocation of soldiers in the indoor combat, tracking the location of firefighter and other emergency personnel in rescue missions, etc.

Abstract: Methods and systems for configuring ad-hoc networks, especially a self-configuring wireless sensor networks, are described. The network has an initial number of anchors with known positions that broadcast a signal. The signals are received by distributed nodes whose position is not yet known. The nodes rank the received signal based on a Quality of Link (QoL; received signal strength) and compute a Quality of position Estimate (QoE) for the node. The node with the best QoE is elevated to anchor. This process gradually increases the number of available anchors in the network and hence the position accuracy for additional nodes. The system can be used for geolocation of soldiers in the indoor combat, tracking the location of firefighter and other emergency personnel in rescue missions, etc.