摘要:
A technique is used in a wideband wireless communication system (100). In some embodiments available channels are determined (310) and one is selected (315) for assignment to each of a set of communication units based on a relative frequency path loss for each available channel. In some embodiments a communication unit is assigned (505) a channel selected from among available channels and a relative signal loss parameter of the communication unit, such as transmit power, is adjusted (510), based on a relative frequency path loss determined from the channel frequency of the assigned channel. In other embodiments, transmit information is split (705) into a plurality of data streams, each characterized by an associated relative signaling sensitivity, and each data stream is assigned (715) to one of a plurality of the transmit channels, wherein data streams are assigned channels of decreasing channel frequencies in order of decreasing associated relative signaling sensitivities of the data streams.
摘要:
An orthogonal frequency division multiplexing (OFDM) transmitter method, consistent with certain embodiments of the present invention arranges OFDM data symbols representing data bits for transmission in a packet. A prescribed pattern of OFDM data symbols are removed (212) and replaced (216) with pilot symbols. The packet is then transmitted (220) to an OFDM receiver that receives the packet (224) and determines a channel correction factor from the pilot pattern. The receiver then estimates a plurality of channel correction factors, one for each of the plurality of OFDM symbols representing data (228) and uses these correction factors to correct the OFDM symbols representing data (232). Arbitrary data are then inserted in place of the pilot symbols (236). The OFDM symbols representing data along with the arbitrary data are then decoded using an error correction decoder that corrects the errors induced by substitution of the pilot symbols for data symbols (240).
摘要:
An Orthogonal Frequency Division Multiplexer (OFDM) transmitter and receiver apparatus consistent with certain embodiments of the present invention receives data to be transmitted and maps (204) a first portion of the data to a first polarization state and a second portion of the data to a second polarization state. A first transmitter (216) transmits the first portion of the data as a set of first OFDM subcarriers using an antenna (230) exhibiting a first polarization. A second transmitter (234) transmits the second portion of the data as a set of second OFDM subcarriers using an antenna (240) exhibiting a second polarization, wherein the first polarization is orthogonal to the second polarization. A receiver apparatus uses a first antenna (302) exhibiting the first polarization and a second antenna (306) exhibiting the second polarization. A first OFDM receiver (310) receives a first set of polarized OFDM subcarriers from the first antenna (302) while a second OFDM receiver (324) receives a second set of polarized OFDM subcarriers from the second antenna (306). A decoder (330) decodes the first and second sets of OFDM subcarriers and combines them into a stream of data.
摘要:
A method (20 or 500) and system (200) for method for computing wireless signal diffraction in a three-dimensional space can include the steps of selecting at least a source point, finding (19) sinkpoints that fail to have a line-of-sight path to the source point and storing the sinkpoints found, placing (21) diffraction points on all edges of a three-dimensional geometry, and building (24) a visibility matrix based on weighted paths for all source points and all sink points. The method can further include applying (25) a path finding algorithm on the visibility matrix for each sink point to all source points and storing store optimal paths for each source point to all sink points if they exist. The method can further include determining (23) if a last source point is selected before building the visibility matrix.
摘要:
An antenna system (205) includes an antenna structure (215), a receiver (220), and an antenna system controller (225). The antenna structure includes an arrangement of antennas (237), a signal combiner (240), and a switching matrix (235). The arrangement of antennas is designed to have a set of antenna element separations that are optimized to provide lowest correlation coefficients of intercepted radio signals for a corresponding set of electromagnetic environment types that vary from a very low density scattering environment to a maximum density scattering environment. The antennas (230), (231), (232), (233), (234) in the antenna arrangement each include at least one element that has a common polarization. There is at least one antenna that is a dual polarized antenna. The antenna system selects an antenna element pair that corresponds to the environment type which it is operating and thereby receives a best combined signal.
摘要:
A method (600) and simulation tool (200) having enhanced accuracy and speed for simulation using ray launching in a mixed environment (20) by using adaptive ray expansion mechanisms can include a memory (204) coupled to a processor (202). The processor can select (602) a target area within the mixed environment and modify (604) the propagation properties of the adaptive ray expansion mechanisms according to characteristics classified for the target area. The processor can further classify characteristics for the target area by transmitting and reflecting rays for indoor building regions and for outdoor building regions. The number of bounces or a power level threshold assigned to a transmitted ray is a function of the environment where it propagates. The simulation tool can determine the target area or a region of interest by using a global positioning service device (230) externally attached to a device performing functions of the simulation tool.
摘要:
Communication systems include a transmitter that modulates a radio signal transmitted from two differently polarized antennas during a state time in which a wave state of the radio signal conveys information and is based on one or more polarization states selected from a constellation of polarization states comprising at least three polarization states. The communication system includes a receiver that intercepts the radio signal by two differently polarized antennas during the state time, and demodulates the signal. The polarization states may identify user devices or may quantify a portion of the information intended for a user device.
摘要:
A subscriber device (10) includes one or more sensors (102) for measuring a object electromagnetic characteristic, such as conductivity, permittivity or permeability. A controller (104) stores the object electromagnetic parameter in memory (106) and, operating in accordance with a performance enhancement routine stored in the memory (106), enhances operation of the subscriber device (10) in accordance with the electromagnetic parameter. The controller (104) may do this by adjusting the power of an amplifier (112), the frequency of a synthesizer (114) or the impedance of an antenna (110). A software program controlling the subscriber device and a corresponding method are described.
摘要:
A method (600) and simulation tool (200) having enhanced accuracy and speed for simulation using ray launching in a mixed environment (20) by using adaptive ray expansion mechanisms can include a memory (204) coupled to a processor (202). The processor can select (602) a target area within the mixed environment and modify (604) the propagation properties of the adaptive ray expansion mechanisms according to characteristics classified for the target area. The processor can further classify characteristics for the target area by transmitting and reflecting rays for indoor building regions and for outdoor building regions. The number of bounces or a power level threshold assigned to a transmitted ray is a function of the environment where it propagates. The simulation tool can determine the target area or a region of interest by using a global positioning service device (230) externally attached to a device performing functions of the simulation tool.
摘要:
A system and method for determining a most likely material composition of an object (102). At least one respective stored radiation polarization transformation (500) is stored for at least one material composition at a plurality of wavelengths. A transmitted electromagnetic signal (112) with at least one wavelength within the plurality of wavelengths and that has a predetermined transmitted polarization profile is transmitted. The transmitted signal (112) encounters an object (102) and is received as at least one received signal (116, 118). Processing determines a respective received polarization for each of the at least one wavelength of the received signal (116, 118), determines a respective calculated polarization transformation between the transmitted polarization profile and the received polarization of the respective wavelength, for each of the at least one wavelength,. The processing also compares the respective calculated polarization transformations to the at least one respective stored radiation polarization transformations (500) for at least one of the plurality of material compositions and based on those comparisons, estimates a most likely material composition for the object (102).