Airespace, Inc.

Cisco Technology, Inc.

Cisco Systems Inc.

Gregg Scott Davi

Paul F Dietrich

Robert J Friday

Bretton Lee Douglas

Alexander H Hills

Bhautik Doshi

Raymond Todd Truitt

A wireless node location mechanism that defines a search region to optimize the computations associated with estimating the location of a given wireless node. According to one implementation, a coverage map associated with each radio receiver that records signal strength data is defined out to a threshold signal strength level. Before computing the estimated location of a given wireless nodes, a search region is defined based on the intersection of the coverage maps associated with each radio receiver that detects the wireless node. Some implementations use information provided by the fact that certain radio receivers did not detect the wireless node to further optimize the location estimate. By defining a search region, which is a generally small area relative to the space encompassed by an entire RF environment, the present invention provides several advantages, such as reducing the processing time and/or power to compute estimated locations for wireless nodes.

Wireless node location mechanism featuring definition of search region to optimize location computation

A wireless node location mechanism that employs a differential signal strength metric to reduce the errors caused by variations in wireless node transmit power, errors in signal strength detection, and/or direction-dependent path loss. As opposed to using the absolute signal strength or power of an RF signal transmitted by a wireless node, implementations of the location mechanism compare the differences between signal strength values detected at various pairs of radio receivers to corresponding differences characterized in a model of the RF environment. One implementation searches for the locations in the model between each pair of radio receivers where their signal strength is different by an observed amount.

Enhanced wireless node location using differential signal strength metric

Methods, apparatuses and systems directed to providing network management information to wireless access points in a wireless network. In one implementation, a wireless client interrogates a wireless access point for its MAC address, for service set identifier (SSID) information, and/or for authentication-related information. If the wireless client determines that the wireless access point is the correct wireless access point, the wireless client polls sensors for physical environment and parameter (PEP) data, which the wireless client then transmits to the wireless access point.

Method and apparatus for transferring network management information to wireless nodes

In one embodiment, a method includes displaying a geographical map illustrating locations of a plurality of wireless nodes of a mesh network; displaying a hierarchically-arranged filter that shows a hierarchical relation of the plurality of wireless nodes; receives a filter configuration; and displaying in the geographical map a subset of the plurality of wireless nodes based on the filter configuration.

Graphical selection of information display for wireless mesh hierarchies

Methods, apparatuses and systems directed to securing a wireless network environment from eavesdropping and other unauthorized activities. One implementation prevents or disrupts meaningful access to information contained in WLAN RF signals that escape from a given physical space during operation of the wireless network. One implementation utilizes overlay RF signals transmitted on one or more operating channels of the WLAN to overpower or mask the internal RF signals escaping from a defined security line or perimeter. One implementation monitors the RF energy escaping to dynamically adjust the power of the overlay signal as required. Implementations of the invention can secure the outer perimeter of an office within a building, or even the outer perimeter of an entire building.

Wireless network perimeter security system using overlaying radio frequency signals

A wireless node location mechanism that dynamically adapts to changes to a surrounding physical environment that affect the propagation of radio signals. The wireless node location mechanism assesses radio signals from transmitters associated with a wireless node location infrastructure to adjust one or more parameters used to estimate location of a wireless node. In one implementation, path loss exponents are re-computed based on the signals transmitted between infrastructure radio transceivers. These path loss exponents are used, in one implementation, to compute the distance between a wireless node and a given infrastructure radio transceiver and, ultimately, to determine the location of the wireless node based on triangulation. In one implementation, path loss exponents are computed on demand based on the signals observed between infrastructure radios that detect the wireless node whose location is to be estimated.

Wireless node location mechanism responsive to observed propagation characteristics of wireless network infrastructure signals

Methods, apparatuses, and systems directed to a wireless node location mechanism that uses a signal strength weighting metric to improve the accuracy of estimating the location of a wireless node based on signals detected among a plurality of radio transceivers. In certain implementations, the wireless node location mechanism further incorporates a differential signal strength metric to reduce the errors caused by variations in wireless node transmit power, errors in signal strength detection, and/or direction-dependent path loss. As opposed to using the absolute signal strength or power of an RF signal transmitted by a wireless node, implementations of the present invention compare the differences between signal strength values detected at various pairs of radio receivers to corresponding differences characterized in a model of the RF environment. One implementation of the invention searches for the locations in the model between each pair of radio receivers where their signal strength is different by an observed amount.

Location of wireless nodes using signal strength weighting metric

Methods, apparatuses and systems directed to optimizing vector models for use in modeling RF propagation in desired physical environments. In one embodiment, the present invention can operate on pre-existing vector models. In other implementations, the present invention facilitates the conversion of raster images of buildings and other physical locations to vector formats for use in connection with the computational modeling of radio-frequency (RF) propagation. According to certain embodiments, the present invention is implemented within the context of a location diagram editing application that supports a line recognition filter, a snap filter and a merge filter which a user may individually select and configure. As discussed more fully below, the line recognition filter operates on the vector objects to adjust near-vertical lines (as defined by a configurable threshold angle) to vertical, and near-horizontal lines to horizontal. In some configuration modes, the line recognition filter may also delete lines that are oriented at an angle greater than a threshold from the x-axis and y-axis to, for example, clean up vector objects corresponding to text and other elements that are usually analytically irrelevant to modeling RF propagation. The snap filter, in one implementation, operates to extend closely spaced objects that are oriented within a threshold distance from each other. The merge filter operates, in one implementation, to merge closely spaced parallel lines to, for example, adjust the vector file to correctly model a wall with a single vector object. In one implementation, the output resulting from the invention is a vector file that has each wall accorded a given wall type, and is optimized for use in connection with an RF prediction engine.

Growing community of inventors

Milpitas, CA, United States of America

Gregg Scott Davi