141 results about "Radio propagation" patented technology

A system and method for design, tracking, measurement, prediction and optimization of data communications networks includes a site specific model of the physical environment, and performs a wide variety of different calculations for predicting network performance using a combination of prediction modes and measurement data based on the components used in the communications networks, the physical environment, and radio propagation characteristics.

A method for estimating position using WLAN access point radio propagation characteristics in a WLAN location based service is provided. A location-based services system has a plurality of Wi-Fi access points in a target area. The Wi-Fi access points are positioned at geographic locations and have signal coverage areas. A method of characterizing at least one of the Wi-Fi access points comprises determining the geographic location of the Wi-Fi access point, dividing the signal coverage area of the Wi-Fi access point into at least one section, and determining radio propagation characteristics for each section. The radio propagation characteristics of each section characterize a radio channel of the Wi-Fi access point, and the characterization can be used in a location algorithm.

Apparatus and methods for transferring audio between a headset and electronic equipment over an optical link. The apparatus includes an electro-optical interface for electrically connecting to the electronic equipment, an optical link, and an electro-optical headset. Audio from the electronic equipment modulates a light source in the electro-optical interface. A modulated light signal is transmitted through the optical link to the electro-optical headset where it is demodulated and reproduced as the original audio in the ear of a user wearing the headset. Also, another audio from the user's mouth produces another modulated light signal in the electro-optical headset. The other modulated light signal is transmitted through the optical link to the electro-optical interface where it is demodulated to provide the other audio to the electronic equipment. The non-electrical optical link may improve audible communications between the electronic equipment and the headset in radio-frequency noisy environments. Also, the non-electrical optical link may prevent coupling with an aerial of the electronic equipment and improve radio propagation.

A base station used in a relay transmission system is disclosed. The base station includes a metric provision unit providing a metric indicating radio propagation conditions of a user equipment terminal; a relay information generation unit generating a relay information for the user equipment terminal based on the metric, the relay information indicating whether an uplink signal is to be transmitted via one or more relay stations; a scheduling unit generating an allocation plan of radio resources based on the relay information; and a control signal transmission unit transmitting a control signal including a scheduling information indicating the allocation plan.

The present invention provides methods and apparatus for a wireless system broadcasting a plurality of data packets to a wireless terminal as the wireless terminal performs a handover in order to support a service. Corresponding data packets are sent in bursts from base stations to the wireless terminal. The data packets are encoded with a forward error correcting (FEC) code, thus generating encoded symbols. When the wireless terminal executes a handover from the first base station to the second base station, some of the encoded symbols (that are contained in the bursts of data packets) may be lost or may be corrupted, as result of practical network considerations and radio propagation characteristics. Consequently, the wireless terminal decodes the received data packets in accordance with the FEC code so that missing or corrupted encoded symbols may be determined.

An estimation apparatus for estimating a channel response of a radio propagation path using a received signal including a first known signal, comprises a generator which generates a reference signal matrix, a calculator which calculates a generalized inverse matrix of the reference signal matrix including singular values which exceed a preset threshold value, an estimation unit configured to estimate an impulse response of the radio channel modeled using a transversal filter based on the first known signal and the generalized inverse matrix, and a converter which converts the estimated impulse response into a frequency-domain signal to acquire a frequency transfer function of the channel.

At base station 101, information signals for mobile station (1) are distributed, each spread with a different spreading code then transmitted from two antennas (3) and (4) assumed under good condition in radio propagation. In mobile station (1), composed waves of both signals are received and each is despread with respective spreading code, as well as in mobile station (2). According to it, it is possible to transmit the same information from a plurality of different antennas at the same time, which prevents the deterioration in communication quality in the case where a wrong antenna is selected or the radio propagation condition varies fast.

Parameters of radio propagation between a mobile terminal and at least one fixed transceiver are measured. Report messages indicating at least a part of the measured parameters, in accordance with a mode of reporting specified by the radio network controller are transmitted to the radio network controller. An estimate of speed of movement of the mobile terminal is obtained at the radio network controller. The report messages are processed at the radio network controller so as to determine, by taking account of the said estimate of speed, a mode of reporting to be specified for a part at least of the report messages.

A signal-of-opportunity location device (SOLD) that may be situated in a complex radio propagation environment with multiple RF signal obstructions receives RF signals from a distant transmitter. The RF signals from the distant transmitter interact with obstructions in the propagation environment local to the SOLD. The local obstructions perturb the RF signals causing the RF signals to exhibit near field behavior in the complex radio propagation environment. The SOLD receives the locally perturbed signals. The SOLD detects signal characteristics of RF signal components of the received signals and compares these signal characteristics with reference data in a reference data store to determine the current location of the SOLD.

A CDMA radio system uses an adaptive filter in a receiver to mitigate multipath radio propagation and to filter out interfering signals. Characteristics of an initial stage of the filter preferably are determined by cross correlation of a generated pilot signal and the input signal with the integration of the correlation performed over a time period selected to be an integral number of symbol periods. The integration causes the portions of the cross correlation corresponding to the user subchannels to average substantially to zero, so that the pilot channel signal correlation is the primary contribution to the signal used to characterize the channel to establish the coefficients of the adaptive filter for the receiver.

The invention discloses a fast calculation method for dynamic plasma sheath radio wave propagation. The method comprises the following steps of establishing a mathematical model of a dynamic plasma sheath electron density based on a physical mechanism of the change speed of the electron density; then adopting a quasi-steady-state monte carlo method and a classical electromagnetic computing method on this basis to acquire a time-varying field intensity result of radio wave propagation of this complex random change medium. The invention is a simple, effective and fast radio wave calculation method, and can solve the radio wave propagation calculation of the dynamic plasma and avoid the high difficulty and high complexity by directly using a random medium modeling method to calculate.

A synthesized gain in a resending operation can be improved significantly by relatively simple control when resending control is applied upon executing of a transmission diversity using CDD. A radio communication apparatus equipped with a plurality of antennas and for performing communication by MIMO, includes a phase shift amount assigning section 18 for executing a CDD process to assign a cyclic phase shift to a transmission signal on a frequency axis, a response signal demodulator 16 for demodulating ACK/NACK received from a destination station, and outputting control information about a resending operation when NACK is received and a reception is failed, and an initial phase controller 17 for setting an offset to a phase shift at a time of CDD process in response to a number of transmission times in resending control such that a predetermined offset, which is produced by adding a phase difference from a signal transmitted from other antenna to the phase shift, is assigned to a signal transmitted from the antenna over a full frequency band, wherein a frequency characteristic of a radio propagation path at a time of resending is changed every time of transmission times.

A wireless communications apparatus (100) includes: antennas (111, 112, and 113); a threshold identifying unit (141) which measures a first radio propagation environment parameter by using a specific directional pattern, and identifies a threshold, from among thresholds, which corresponds to the measured first radio propagation environment parameter; a directional pattern selecting unit (142) which performs test communications by sequentially switching directional patterns, and selects a directional pattern having an actual throughput, calculated from a measurement value of a second radio propagation environment parameter, greater than the threshold; and a threshold adjusting unit (143) which changes the threshold identified by the threshold identifying unit (141), according to the number of test communications that is the number of the directional patterns used for the test communications performed by the directional pattern selecting unit (142).

An impulse radio system estimates a separation distance between an impulse radio transmitter and an impulse radio receiver. The system includes an impulse transmitter that transmits an impulse signal having an ultra-wideband frequency characteristic. An impulse receiver spaced from the transmitter receives the transmitted impulse signal and measures a signal strength of the received impulse signal. The receiver estimates the separation distance based on the measured signal strength. The receiver classifies a signal propagational/multipath environment using the received impulse signal, and then selects a radio propagation path loss model corresponding to a classified multipath environment. The receiver translates the measured signal strength to a separation distance based on the selected radio propagation path loss model.

Under present circumstances, where an increasing number of wireless communication systems employ the QAM method as a modulation method for frequency use efficiency enhancement as the speed of information transmission in the wireless communication systems increases, it is an object of the present invention to provide a channel estimation method for estimating a channel efficiently and accurately and establishing communication at high quality, that is, providing communication with excellent error rate characteristics. To achieve the above object, the present invention improves characteristics by calculating the channel estimation results variously for all data signal symbols and using them for demodulation. To accomplish the object, the present invention also pays attention to the frequency characteristics of fading in a radio propagation path and enhances the accuracy in channel estimation result calculation by using a band pass filter for eliminating the thermal noise that would increase the estimation error.

A process for forming a wireless mesh network (WMN) in which client coverage is calculated using a point-to-point propagation loss model and optimal routing and power allocation is determined to quantify the value of network flow. In one embodiment, the process calculates loss based on access point locations, operating characteristics and terrain and environment information. In one embodiment, the network flow and coverage subproblem values are combined via a penalty function. The process creates WMN topologies that maximize client coverage area by choice of access point locations, subject to constraints on network flow and power allocation, number and technical capabilities of access points, background and environmental noise, and radio propagation over terrain.

A CDMA radio system uses an adaptive filter in a receiver to mitigate multipath radio propagation and to filter out interfering signals. Characteristics of an initial stage of the filter preferably are determined by cross correlation of a generated pilot signal and the input signal with the integration of the correlation performed over a time period selected to be an integral number of symbol periods. The integration causes the portions of the cross correlation corresponding to the user subchannels to average substantially to zero, so that the pilot channel signal correlation is the primary contribution to the signal used to characterize the channel to establish the coefficients of the adaptive filter for the receiver.

The invention discloses a spectrum detection strategy for a cognitive radio (CR) system, which is realized in a way that: by utilizing the differences among radio propagation channels and the theories of subset partition and linear programming, selecting the optimal strategy of the detected channel set, realizing the optimal detection on the authorized user among every CR users, reporting the detection result to a CR base station, and determining whether an authorized user signal exists by utilizing the CR base station, thereby determining whether the spectrum is idle. The invention also provides a cognitive radio system, a base station and a terminal device. By implementing the spectrum detection strategy, the base station and the terminal device for the cognitive radio system, the invention enhances the spectrum detection performance of the CR system, realizes the detection on the CR system within all bands, and enhances the overall detection performance of the system. In addition, the invention can be used in a centralized network structure, and is applicable to Standard IEEE802.22.

The present invention relates to a mobile station that controls a transmission rate of user data to be transmitted to a base station. The mobile station according to the present invention includes: a transmission rate control unit configured to decide an instantaneous transmission rate of the user data, based on a parameter notified from a network during establishment of a call, a radio propagation path quality of a radio propagation path between the mobile station and the base station, an average radio propagation path quality of the radio propagation path, and a factor related to a transmission rate, a transmission power or a transmission power ratio notified from the base station.