Abstract: In one example embodiment, a method includes obtaining a duration of a first network element scanning period of a first network element for a plurality of first beacons, the plurality of first beacons associated with the different direct energy beams, scanning for the plurality of first beacons over a second network element scanning period of a second network element, the second network element scanning period including a number of first network element scanning periods, the first network element scanning period being part of the number of the first network element scanning periods, receiving at least one of the plurality of first beacons during the number of the first network element scanning periods, determining a preferred first beacon based on the received at least one of the plurality of first beacons and transmitting an indication of the preferred first beacon to a base station.

Abstract: In one example embodiment, a method includes transmitting a plurality of first beacons over a first scanning period, the plurality of first beacons associated with different direct energy beams, the transmitting including, transmitting the plurality of first beacons over sub-periods of the first scanning period, respectively; obtaining an indication of a preferred first beacon, the preferred beacon being received by a network element during the transmitting of the plurality of beacons over the first scanning period; and communicating with the element during a scheduled portion of a first data communication period using the beam associated with the preferred first beacon, a length of the first scanning period and a length of the first data communication period forming a length of a time transmission interval.

Abstract: In one example embodiment, a method includes transmitting a plurality of first beacons over a first scanning period, the plurality of first beacons associated with different direct energy beams, the transmitting including, transmitting the plurality of first beacons over sub-periods of the first scanning period, respectively; obtaining an indication of a preferred first beacon, the preferred beacon being received by a network element during the transmitting of the plurality of beacons over the first scanning period; and communicating with the element during a scheduled portion of a first data communication period using the beam associated with the preferred first beacon, a length of the first scanning period and a length of the first data communication period forming a length of a time transmission interval.

Abstract: In one example embodiment, a method includes obtaining a duration of a first network element scanning period of a first network element for a plurality of first beacons, the plurality of first beacons associated with the different direct energy beams, scanning for the plurality of first beacons over a second network element scanning period of a second network element, the second network element scanning period including a number of first network element scanning periods, the first network element scanning period being part of the number of the first network element scanning periods, receiving at least one of the plurality of first beacons during the number of the first network element scanning periods, determining a preferred first beacon based on the received at least one of the plurality of first beacons and transmitting an indication of the preferred first beacon to a base station.

Abstract: A leaky repeater access node (LRAN) includes a first directional antenna and a second directional antenna to transmit and receive signals in at least one first frequency band, and a third antenna to transmit and receive signals in a second frequency band. The LRAN also includes first analog components to split a first signal received by the first directional antenna into a first portion and a second portion. The first analog components amplify the first portion and provide the amplified first portion to the second directional antenna. The first analog components also convert the second portion to the second frequency band and provide the converted second portion to the third antenna.

Abstract: Various embodiments provide a method and apparatus for determining tag location by using one or more estimated channel responses (CR) that characterize the wireless channel between the tag and one or more respective anchors. In particular, a tracking server in communication with the anchor(s) determines the tag's location based on a comparison of the estimated CR(s) with a set of stored CRs associated with the anchor(s).

Abstract: A leaky repeater access node (LRAN) includes a first directional antenna and a second directional antenna to transmit and receive signals in at least one first frequency band, and a third antenna to transmit and receive signals in a second frequency band. The LRAN also includes first analog components to split a first signal received by the first directional antenna into a first portion and a second portion. The first analog components amplify the first portion and provide the amplified first portion to the second directional antenna. The first analog components also convert the second portion to the second frequency band and provide the converted second portion to the third antenna.

Abstract: Various embodiments provide a method and apparatus for determining tag location by using one or more estimated channel responses (CR) that characterize the wireless channel between the tag and one or more respective anchors. In particular, a tracking server in communication with the anchor(s) determines the tag's location based on a comparison of the estimated CR(s) with a set of stored CRs associated with the anchor(s).

Abstract: A method of modeling predicted values, at a selected point, of radio fields originating from a source in a geographic area including a plurality of streets and a plurality of buildings includes determining a first path from the source to the selected point, the first path including a first segment, and predicting a value, at the selected point, of a radio field originating from the source by modeling the first segment as a first waveguide, and at least one of (1) generating a first radio field coupling equation by coupling the first waveguide with a second waveguide, the second waveguide being a model of a second segment, the second segment being included in the first path, and (2) generating a second radio field coupling equation by coupling the first waveguide with an indoor model for modeling radio fields traveling through a building or outer wall.

Abstract: In a method for estimating a channel at a receiver in a wireless communications network, the receiver obtains channel model parameters for a received signal based on raw channel estimates for the received signal, where each raw channel estimate corresponds to an antenna at the receiver. The receiver combines, for each of a plurality of contiguous subcarriers in the wireless communications network, the channel model parameters to generate a first plurality of combined channel model parameters. The receiver then chooses a first set of indices corresponding to combined channel model parameters from among the first plurality of combined channel model parameters having magnitudes passing a combined channel model parameter threshold. The receiver then estimates the channel in a sparse domain based on the first set of indices.

Abstract: In a method for estimating a channel at a receiver in a wireless communications network, the receiver obtains channel model parameters for a received signal based on raw channel estimates for the received signal, where each raw channel estimate corresponds to an antenna at the receiver. The receiver combines, for each of a plurality of contiguous subcarriers in the wireless communications network, the channel model parameters to generate a first plurality of combined channel model parameters. The receiver then chooses a first set of indices corresponding to combined channel model parameters from among the first plurality of combined channel model parameters having magnitudes passing a combined channel model parameter threshold. The receiver then estimates the channel in a sparse domain based on the first set of indices.

Abstract: According to a method for localizing a transmitter inside a building, a transmitter emits rays which undergo multiple reflections with the walls, ceilings and floors of the building. Each of K receivers receives rays from the transmitter, and the receivers estimates the AOA (Angle of arrival), TOA (Time of Arrival) and power of each ray. At least one of the receivers uses a known blueprint of the building and material characteristics of the walls to localize the transmitter to a higher degree of accuracy by applying a backward ray tracing algorithm.

Abstract: According to a method for localizing a transmitter inside a building, a transmitter emits rays which undergo multiple reflections with the walls, ceilings and floors of the building. Each of K receivers receives rays from the transmitter, and the receivers estimates the AOA (Angle of arrival), TOA (Time of Arrival) and power of each ray. At least one of the receivers uses a known blueprint of the building and material characteristics of the walls to localize the transmitter to a higher degree of accuracy by applying a backward ray tracing algorithm.

Abstract: A method and apparatus for reducing the observed rate of change of the channel characteristics in a system with multiple antennas at a mobile terminal. The slowing down of the observed channel fluctuations is effectuated on the downlink by either calculating or receiving signals that have a similar Doppler shift, referred to herein as Doppler-compensatable signals, and processing one or more of the Doppler-compensatable signals to compensate for Doppler shift. The slowing down of the observed channel fluctuations is effectuated on the uplink by pre-compensating symbol streams with the Doppler shift associated with the direction in which they are transmitted, so that the observed Doppler shift of these signals when they are received is reduced or even eliminated.

Abstract: A method and apparatus for reducing the observed rate of change of the channel characteristics in a system with multiple antennas at a mobile terminal. The slowing down of the observed channel fluctuations is effectuated on the downlink by either calculating or receiving signals that have a similar Doppler shift, referred to herein as Doppler-compensatable signals, and processing one or more of the Doppler-compensatable signals to compensate for Doppler shift. The slowing down of the observed channel fluctuations is effectuated on the uplink by pre-compensating symbol streams with the Doppler shift associated with the direction in which they are transmitted, so that the observed Doppler shift of these signals when they are received is reduced or even eliminated.

Abstract: An omnidirectional ultrasonic microprobe hydrophone is disclosed. Applicans include underwater mine detection, explosive shock testing, high wave number measurements, medical imaging, and therapeutic systems. The apparatus includes at least two lead zirconate titanate (PZT) pressure sensing elements having a plurality of columnar voids formed therein. The pressure sensing elements are deposited on a metallic or nonmetallic substrate which provides mechanical support for the microprobe hydrophone. Electrical connection to the pressure sensing elements is made by deposition of conductors and insulators on the substrate material. Wire bonds are used to attach wire leads for connection to a supporting structure containing a preamplifier. Line arrays and planar arrays of microprobe hydrophone elements are also disclosed.