Motorola Corporation

Motorola Solutions, Inc.

Feng Niu

Spyros Kyperountas

Qicai Shi

Jian C Huang

Neiyer S Correal

Kenneth David Cornett

Yan Huang

Danny O McCoy

Paul Edward Gorday

Frederick L Martin

Vernon Anthony Allen

Wei-Yean Howng

David B Taubenheim

Lance Eric Hester

Wang-Chang A Gu

Oleg Andric

Wayne W Chiou

Timothy Bancroft

Jon Patrick Oliver

During operation a node () that has associated with a network () will periodically broadcast a beacon () during a beacon interval as part of a superframe. The beacon will be periodically broadcast for a first period of time, based on a time it takes for nodes to associate with the network. After the first period of time has passed, the beacon will be switched off for a second period of time, after which, the beacon will again be periodically broadcast.

Method and apparatus for operating a node in a beacon based ad hoc network

A location technique is utilized where channel-model parameters are originally estimated prior to location taking place. Location then takes place using a first set of known-located nodes, and the channel-model parameters are updated based on the distances resulting from the location estimate. Once the channel-model parameters have been updated, location again takes place using a second set of known-located nodes, node distances are calculated based on the produced locations and the channel-model parameters are again updated. This process continues until no significant change is observed between the previous and the newly estimated location, or until a maximum number of iterations is reached.

Method and apparatus for determining the location of a node in a wireless system

A method and apparatus for determining the path loss model of an object within a wireless communication system is provided herein. During operation, a path loss model for a node is generated based on path loss values and corresponding numbers of neighbors of the said node. The path loss model is used to determine a relationship between path loss and distance. With this relationship established, distances to known-located nodes may be obtained by obtaining a path loss to the known-located node. From these distances, a node can then be located.

A method for peer-to-peer ranging and discovery of a rigid body existing in a scatternet having piconets and nodes includes the steps of defining a node () in a piconet () to be a piconet controller (PNC) having controller functions, locating a rigid body seed including the node (), and discovering a rigid body by sequentially downloading controller functions of the piconet controller () to at least one border node. Also provided is a communications node including a receiver for receiving communications from other communications nodes in a communications range (R), a transmitter for sending communications to other communications nodes in the communications range (R), a memory storing at least ranging information and a unique identification for describing the node, and a processor connected to the receiver, to the transmitter, and to the memory, the processor being programmed to carry out the method according to the present invention.

Method for rigid body discovery and peer-to-peer ranging in a scatternet and communications node

A location technique is utilized within a wireless communication system where power measurements from various nodes are weighted to determine a node's location. An iterative location process is executed where as more and more nodes are heard from, a node will re-locate itself in order to improve location accuracy.

A method for locating nodes in a multi-hop sensor network forms a rigid body (RB, RB, RB) and, from the nodes, utilizes the rigid body to decide if a node is locatable. The method obtains a reduced order model (ROM) of the network by categorizing all of the nodes by location status, grouping them based upon the categorizations, and defining and identifying a rigid body from a group. The method further simplifies determinability of node location by forming the rigid body from the nodes based upon the categorized location status. To locate the nodes, the nodes are separated from one another into subsets dependent upon characteristics (). Then, groups are formed from one subset () and the rigid body is formed from a group (). The ROM is formed from the rigid body () and a location capability of the rigid body is evaluated based upon the ROM ().

Reduced order model node location method for multi-hop networks

A method and system is provided for determining a location for each of a plurality of units, which are sub-divided into more than one sub-net groupings, that each include two or more units. Within each sub-net grouping, measured range information between units within the sub-nets and one or more reference units is gathered in at least a selected one of the units. The selected one of the units then estimates a location for each of the units, which minimizes any error in the measured ranges between the units in each of the corresponding sub-nets.

Method and system for determining a location of a plurality of units using sub-divided unit groupings

A method for reducing communications in a peer-to-peer wireless network having nodes includes sending an RTS-TOA ranging communication from a first node (N) in a node group to another node (Nr, I) in the group, receiving the RTS-TOA communication with the second node (Nr, I) and sending a multi-cast CTS-TOA/RTS-TOA ranging communication from the second node (Nr, I) as a reply to the received RTS-TOA communication, and successively and sequentially repeating the multi-cast sending step for each of the nodes. A CTS-TOA message is a reply to the received RTS-TOA message and, simultaneously, is an RTS-TOA ranging communication to a new destination node (J). The method applies for a randomized communications approach when node identifications are not sequenced and to a sequential approach where nodes are sequenced, and also applies to completely connected and multi-hop networks. Also provided is a node for carrying out the method of the present invention.

Distributed MAC protocol facilitating collaborative ranging in communications networks

A method and location determination module is provided for determining a location of one of a plurality of units using neighbor lists. Each unit is communicatively coupled to at least some of the other plurality of units, where at least some of the plurality of units are reference units, whose locations are known. The units communicate with other nearby units within communication range, to establish neighbor lists. A unit to be located then identifies an aggregate value corresponding to the number of occurrences of the reference units in the neighbor list of the unit to be located and the neighbor lists of each of a group of associated units. The location of the unit to be located is then determined, based upon the known locations of the reference units and the number of identified occurrences of the reference units in the corresponding neighbor lists.

Method and apparatus for determining the location of a unit using neighbor lists

A method and apparatus for determining the location of a node within a communication system is provided herein. During operation, reference nodes () having known locations are utilized to locate 'blind' nodes () whose location is to be determined. More particularly, a blind node () wishing to determine its location will measure a plurality of path losses between itself and a plurality of reference nodes (). These reference nodes' locations will then be mathematically weighted by the path loss between these reference nodes () and the blind node (). The location of the blind node () is a sum of the mathematically weighted reference nodes' locations.

Method and apparatus for determining the location of a node in a wireless title system

A method and system is provided for determining a location for each of a plurality of units, which is selected from one of multiple sets of locations, which are each estimated based upon different initial location estimates. The selected set of locations includes the set which has the minimum error value, where the error value is based on the aggregate of the differences between the range determined from the estimated locations and the measured range. By using different sets of initial location estimates, there is a greater chance that at least one of the sets of initial location estimates will avoid any local minimums and produce a more accurate estimate of unit locations.

Method and system for determining a location using a plurality of selected initial location estimates

A first type of MEMS resonator adapted to be fabricated on a SOI wafer is provided. A second type of MEMS resonator that is fabricated using deep trench etching and occupies a small area of a semiconductor chip is taught. Overtone versions of the resonators that provide for differential input and output signal coupling are described. In particular resonators suited for differential coupling that are physically symmetric as judged from center points, and support anti-symmetric vibration modes are provided. Such resonators are robust against signal noise caused by jarring. The MEMS resonators taught by the present invention are suitable for replacing crystal oscillators, and allowing oscillators to be integrated on a semiconductor chip. An oscillator using the MEMS resonator is also provided.

MEMS resonators and method for manufacturing MEMS resonators

Torsional hinge support beams ( ) that are corrugated, perforated and/or have non-uniform width are provided. The support beams are useful in flexural beam resonators ( ), in which they serve to support the main flexural mode-vibrating beam ( ). The support beams have phase lengths equal to an odd multiple of &pgr;/2, preferably the phase lengths are about equal to &pgr;/2 at the operating frequency of the resonators. Owing to the corrugations, the lengths of the support beams are shorter than comparable solid straight edge support beams. The short lengths of the support beams reduce the overall area occupied by the resonators and allow higher bias voltage to be employed in order to obtain greater electromechanical coupling.

Reduced size, low loss MEMS torsional hinges and MEMS resonators employing such hinges

Microelectromechanical resonators that can be fabricated on a semiconductor die by processes normally used in fabricating microelectronics (e.g., CMOS) circuits are provided. The resonators comprises at least two vibratable members that are closely spaced relative to a wavelength associated with their vibrating frequency, and driven to vibrate one-half a vibration period out of phase with each other, i.e. to mirror each others motion. Driving the vibratable members as stated leads to destructive interference effects that suppress leakage of acoustic energy from the vibratable members into the die, and improve the Q-factor of the resonator. Vibratable members in the form of vibratable plates that are formed by deep anisotropic etching one or more trenches in the die are disclosed. Embodiments in which two sets of vibratable plates are spaced by &frac12; the aforementioned wavelength to further suppress acoustic energy leakage, and improve the Q-factor of the resonator are disclosed.

High Q factor MEMS resonators

Dispersive surface antenna structures ( ) provide improved selectivity and increased control over bandwidth. Antenna structures ( ) include a wraparound piece of conductive material located perpendicular to a ground plane ( ). Ground posts ( ) extend up from the ground base ( ) and capacitively couple to a front conductive surface ( ) of the antennas ( ). First and second conductive back surfaces ( ), ( ) are capacitively coupled across a gap ( ) along the back of the antennas ( ). The size, width, and location of the gap ( ) along with the ground posts ( ) provide increased control over antenna performance.

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Weston, FL, United States of America

Feng Niu