Abstract: This inventions provides techniques for estimating both temporal and spectral channel fluctuations with the duration of a data symbol. Certain pulse shaping functions are Discrete Prolate Spheroidal Sequences (DPSSs) and are used primarily because of their relatively limited Inter-Symbol Interference (ISI) properties. During reception, these properties allow one or more parameters of a joint time-frequency channel model to be more easily determined. Once the one or more parameters are determined, they can be applied to received symbols to correct the temporal fluctuations, spectral fluctuations, or both of the channel over which a communication took place. The techniques may be adapted for the Multiple-In, Multiple-Out communication situation.

Abstract: This inventions provides techniques for estimating both temporal and spectral channel fluctuations with the duration of a data symbol. Certain pulse shaping functions are Discrete Prolate Spheroidal Sequences (DPSSs) and are used primarily because of their relatively limited Inter-Symbol Interference (ISI) properties. During reception, these properties allow one or more parameters of a joint time-frequency channel model to be more easily determined. Once the one or more parameters are determined, they can be applied to received symbols to correct the temporal fluctuations, spectral fluctuations, or both of the channel over which a communication took place. The techniques may be adapted for the Multiple-In, Multiple-Out communication situation.

Abstract: This inventions provides techniques for estimating both temporal and spectral channel fluctuations with the duration of a data symbol. Certain pulse shaping functions are Discrete Prolate Spheroidal Sequences (DPSSs) and are used primarily because of their relatively limited Inter-Symbol Interference (ISI) properties. During reception, these properties allow one or more parameters of a joint time-frequency channel model to be more easily determined. Once the one or more parameters are determined, they can be applied to received symbols to correct the temporal fluctuations, spectral fluctuations, or both of the channel over which a communication took place. The techniques may be adapted for the Multiple-In, Multiple-Out communication situation.

Abstract: For use in a wireless communication network that includes a transmitter having a multi-element transmit antenna array, an information hiding system and a method of hiding information. In one embodiment, the information hiding system includes an information spreading subsystem that is configured to scramble the information across the multi-element transmit antenna array. The information hiding system further includes a coherence modification subsystem that is configured to reduce channel coherence randomly during transmission of the scrambled information via the multi-element transmit antenna array. By hiding the information, the information hiding system advantageously reduces an unauthorized eavesdropper's ability to determine the contents of the transmitted information.

Abstract: Systems and techniques for location determination. A plurality of tags emitting radio frequency signals are dispersed throughout a region, such as a building, within which a user's location is to be determined. The radio frequency signals emitted by the tags include information that can be used to identify the location in which the tags axe placed, or simply to distinguish the tags from one another. A portable device receives signals from the tags and provides the signal information to a location server that computes the location of the portable device by comparing the signal information received from the portable device to a map of location venus stored signal information, and identifies the location of the portable device as the location for which the stored signal information best matches the signal information received from the portable device.

Abstract: A method of wireless communication is disclosed, in which polarization diversity can be utilized to improve fading performance or to increase the capacity of the communication channel in a scattering environment. Complementary signal information is impressed upon, or derived from, corresponding electric and magnetic polarized field components of a transmitted or intercepted electromagnetic wave. Four, five, or even six independent signal channels can thereby be utilized for communication using a localized antenna arrangement.

Abstract: A compact antenna and a communication unit having the same comprises one or more input feeds and one or more sets of elements. Each set of elements is coupled to one or more of the input feeds, and each set of elements has a property that input signals applied to input feeds coupled to the set of elements causes a directed beam to be emitted. At least one given element of the set or sets of elements has a largest dimension, and a smallest wavelength to be emitted from the antenna is larger than the largest dimension for the given element. The antenna is adapted to simultaneously transmit the input signals, and generally more than two input signals. When a concentration region for a directed beam is large enough, more than one degree of freedom can be contained in the concentration region. Techniques are presented for designing the compact antenna.

Abstract: A compact antenna and a communication unit having the same comprises one or more input feeds and one or more sets of elements. Each set of elements is coupled to one or more of the input feeds, and each set of elements has a property that input signals applied to input feeds coupled to the set of elements causes a directed beam to be emitted. At least one given element of the set or sets of elements has a largest dimension, and a smallest wavelength to be emitted from the antenna is larger than the largest dimension for the given element. The antenna is adapted to simultaneously transmit the input signals, and generally more than two input signals. When a concentration region for a directed beam is large enough, more than one degree of freedom can be contained in the concentration region. Techniques are presented for designing the compact antenna.

Abstract: Techniques for location determination are described. A plurality of tags emitting radio frequency signals are dispersed throughout an region, such as a building, within which a user's location is to be determined. The radio frequency signals emitted by the tags include information that can be used to identify the location in which the tags are placed, or simply to distinguish the tags from one another. A portable device receives signals from the tags and provides the signal information to a location server that computes the location of the portable device by comparing the signal information received from the portable device to a map of location versus stored signal information, and identifies the location of the portable device as the location for which the stored signal information best matches the signal information received from the portable device.

Abstract: This inventions provides techniques for estimating both temporal and spectral channel fluctuations with the duration of a data symbol. Certain pulse shaping functions are Discrete Prolate Spheroidal Sequences (DPSSs) and are used primarily because of their relatively limited Inter-Symbol Interference (ISI) properties. During reception, these properties allow one or more parameters of a joint time-frequency channel model to be more easily determined. Once the one or more parameters are determined, they can be applied to received symbols to correct the temporal fluctuations, spectral fluctuations, or both of the channel over which a communication took place. The techniques may be adapted for the Multiple-In, Multiple-Out communication situation.

Abstract: For use in a wireless communication network that includes a transmitter having a multi-element transmit antenna array, an information hiding system and a method of hiding information. In one embodiment, the information hiding system includes an information spreading subsystem that is configured to scramble the information across the multi-element transmit antenna array. The information hiding system further includes a coherence modification subsystem that is configured to reduce channel coherence randomly during transmission of the scrambled information via the multi-element transmit antenna array. By hiding the information, the information hiding system advantageously reduces an unauthorized eavesdropper's ability to determine the contents of the transmitted information.

Abstract: A method of wireless communication is disclosed, in which polarization diversity can be utilized to improve fading performance or to increase the capacity of the communication channel in a scattering environment. Complementary signal information is impressed upon, or derived from, corresponding electric and magnetic polarized field components of a transmitted or intercepted electromagnetic wave. Four, five, or even six independent signal channels can thereby be utilized for communication using a localized antenna arrangement.

Abstract: E-mail which may be infected by a computer virus is advantageously filtered by incorporating a “Reverse Turing Test” to verify that the source of a potentially infected e-mail is human and not a machine, and that the message was intentionally transmitted by the apparent sender. Such a test may, for example, involve asking a question which will be easy for a human to answer correctly but quite difficult for a machine to do so. The e-mail may be deemed to be potentially infected based on an analysis of executable code which is attached to the e-mail, or merely based on the fact that executable code is attached. The e-mail may also be deemed to be potentially infected based on additional factors, such as, for example, the identity of the sender and past experiences therewith. Spam E-mail may also be advantageously filtered together with virus-containing e-mail with use of a single common filtering system.

Abstract: Base stations transmit corresponding pilot signals identifiable with the corresponding base station, parameters associated with the pilot signals are measured at mobile stations and transmitted back to the base stations on an uplink channel. The measured parameters are shared between the base stations over a separate network. Co-channel transmissions are formulated at the base stations using the measured parameters, such that at least two mobile stations receive respective transmissions on the same channel. Adaptation of the transmission to the changes in propagation reduces co-channel interference. The wireless network is one of a CDMA and a FDMA network.

Abstract: A method of wireless communication is disclosed, in which polarization diversity can be utilized to improve fading performance or to increase the capacity of the communication channel in a scattering environment. Complementary signal information is impressed upon, or derived from, corresponding electric and magnetic polarized field components of a transmitted or intercepted electromagnetic wave. Four, five, or even six independent signal channels can thereby be utilized for communication using a localized antenna arrangement.

Abstract: A method of wireless communication is disclosed, in which polarization diversity can be utilized to improve fading performance or to increase the capacity of the communication channel in a scattering environment. Complementary signal information is impressed upon, or derived from, corresponding electric and magnetic polarized field components of a transmitted or intercepted electromagnetic wave. Four, five, or even six independent signal channels can thereby be utilized for communication using a localized antenna arrangement.

Abstract: Problems of fading in a multi-path environment are ameliorated, and the presence of reflective surfaces is turned from a disadvantage to an advantage, by employing a third polarization direction that effectively creates a third communication channel. This third communication channel can be used to send more information, or to send information with enhanced spatial diversity to thereby improve the overall communication performance. A transmitted signal with three polarization directions is created with a transmitter having, illustratively, three dipole antennas that are spatially orthogonal to each other. A received signal having energy content in three polarization directions is detected by a receiver having, illustratively, three dipole antennas that are spatially orthogonal to each other.

Abstract: Problems of fading in a multi-path environment are ameliorated, and the presence of reflective surfaces is turned from a disadvantage to an advantage, by employing a third polarization direction that effectively creates a third communication channel. This third communication channel can be used to send more information, or to send information with enhanced spatial diversity to thereby improve the overall communication performance. A transmitted signal with three polarization directions is created with a transmitter having, illustratively, three dipole antennas that are spatially orthogonal to each other. To take advantage of the signal with the third polarization direction, the receiver also comprises three mutually orthogonal antenna dipoles.

Abstract: A fuel pellet and a method of manufacturing a fuel pellet capable of burning in either a stoker or pulver furnace, comprising from about 0 to about 80% by weight of cellulosic material, from about 1% to about 50% by weight of densified thermoplastic material, and from about 0 to about 50% by weight of coal. The cellulosic material, densified thermoplastic material and coal are ground from about 80 Mesh to about 200 Mesh, and then blended into a mixture wherein the contents are evenly distributed throughout. Following the blending process, the mixture is forced through a pelletizer. As the pellets are removed from the pelletizer they are immediately cooled so that the densified thermoplastic particles do not melt. The resulting fuel pellets produce from about 10,000 BTU per pound to about 16,000 BTU per pound and leave an ash deposit of about 0 to about 6% by weight, and a sulfur dioxide output of about 0 to about 3% by weight.

Abstract: A fuel pellet and a method of manufacturing a fuel pellet capable of burning in either a stoker or pulver furnace, comprising from about 0 to about 80% by weight of cellulosic material, from about 20% to about 50% by weight of densified thermoplastic material, and from about 0 to about 50% by weight of coal. The cellulosic material, densified thermoplastic material and coal are ground from about 80 Mesh to about 200 Mesh, and then blended into a mixture wherein the contents are evenly distributed throughout. Following the blending process, the mixture is forced through a pelletizer. As the pellets are removed from the pelletizer they are immediately cooled so that the densified thermoplastic particles do not melt. The resulting fuel pellets produce from about 10,000 BTU per pound to about 16,000 BTU per pound and leave an ash deposit from about 0 to about 6% by weight, and a sulfur dioxide output from about 0 to about 3% by weight.