3059 results about "Signal quality" patented technology

A WLAN system adapted to apply QoS differentiation to a media stream to be transmitted from a transmitting station (STA) to a receiving STA of that system. The transmitting STA processes the media stream to generate a base sub-stream and one or more enhancement sub-streams for subsequent transmission over a wireless communication channel and assigns different priorities to different sub-streams. Depending on the channel conditions, the transmitting STA may select to discard, without transmission, portions of data from enhancement sub-streams. The selection process is based on the assigned priority and operates to preserve as much of relatively high-priority data as possible. The receiving STA then processes the received data to generate a reconstructed media stream, which provides signal quality equal to or better than the signal quality supported by the base sub-stream. Advantageously, a WLAN system of the invention is adapted to change signal quality dynamically and incrementally in a manner commensurate with current channel conditions without the need for communication between the higher and lower network layers. In addition, it provides gradual and graceful degradation of signal quality when channel conditions deteriorate as opposed to abrupt degradation inherent in analogous prior art systems.

A processor provides signal quality based limits to a signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, computed as the percentage of total energy contained in the pulse rate fundamental and associated harmonics.

A system, method and computer program product provides for power line communications (PLC) over electric power lines includes a device mountable near an electrical distribution transformer (DT) to provide a high speed interface and communicates with one or multiple access devices, which provide low speed interfaces for analog signals or digital signals over RS 232, RS 485, optical, wireless and Ethernet. The device transmits data to/from these access devices over the electric lines to other repeaters over one or more wires of an electrical line or over multiple lines, and serves to strengthen and improve signal quality. Upon detecting a wire or line is having problems carrying data, the data is sent over other wires, and upon power line failures, wireless backup to mobile/GSM and WiMax networks is utilized. The device permits utilities and others to read electric meters, monitor the power quality of the distribution grid and detect power losses/failures/outages, and permits telecom service providers and others to provide a communications link to cell phone towers, WiFi Access Points and enable broadband Internet and telephony in rural, remote or sparely populated areas.

An active-pulse blood analysis system has an optical sensor that illuminates a tissue site with multiple wavelengths of optical radiation and outputs sensor signals responsive to the optical radiation after attenuation by pulsatile blood flow within the tissue site. A monitor communicates with the sensor signals and is responsive to arterial pulses within a first bandwidth and active pulses within a second bandwidth so as to generate arterial pulse ratios and active pulse ratios according to the wavelengths. An arterial calibration curve relates the arterial pulse ratios to a first arterial oxygen saturation value and an active pulse calibration curve relates the active pulse ratios to a second arterial oxygen saturation value. Decision logic outputs one of the first and second arterial oxygen saturation values based upon perfusion and signal quality.

Packet-based central conference bridges, packet-based network interfaces and packet-based terminals are used for voice communications over a packet-based network. Modifications to these apparatuses can reduce the latency and the signal processing requirements while increasing the signal quality within a voice conference as well as point-to-point communications. For instance, by selecting the talkers prior to the decompression of the voice signals, decreases in the latency and increases in signal quality within the voice conference can result due to a possible removal of the decompression and subsequent compression operations in a conference bridge unnecessary in some circumstances. Further, the removal of the jitter buffers within the conference bridges and the moving of the mixing operation to the individual terminals and/or network interfaces are modifications that can cause lower latency and transcoding within the voice conference.

A cost effective electronically self optimizing antenna system is provided for use with each subscriber unit in both fixed and mobile wireless applications. The smart antenna consists of multiple antenna elements arranged so that individual beams independently cover sections of free space. Collectively, complete coverage of the desired free space is accomplished. The smart antenna uses a relatively narrow beam directed in the appropriate direction thereby reducing interference and improving system capacity. A controller is included which continuously monitors the signal quality and intelligently selects the optimum antenna beam pattern configuration. All telecommunication protocols, both analog and digital, can be accommodated by the controller.

Embodiments of the invention relate to cellular wireless networks and are particularly suited to networks including different types of base stations. So-called femtocell base stations are typically deployed within a subscriber's premises and operate at low transmit power, providing a very limited area of wireless coverage. A femtocell is typically deployed within the area of wireless coverage of a conventional macrocell type of base station, and if handover from a macrocell is performed on the basis of the best signal to noise plus interference ratio, a connection is likely to be transferred to another macrocell rather than to a femtocell. However, in view of the low density of user equipments capable of transceiving with a femtocell, the femtocell could potentially provide a greater data rate to the user equipment terminal than is possible with a macrocell. A cellular wireless network according to an embodiment of the invention employs a method of handover algorithm that has dependence on both a measure of signal quality such as signal to noise plus interference ratio and on a measure of loading of the base station. The handover algorithm is thereby able to weight selection of a base station on the basis of data rate, and intelligently engineer handover to a femtocell.

Over-terminating the differential mode impedance of a differential transmission line, such as an INFINIBAND™ cable, at the receiving end, improves the differential signal integrity for typical variations in termination network impedance component (e.g., resistor) and transmission line characteristics. Eye opening of the differential signal can be made larger with reduced attenuation but increased jitter compared to under-terminating the differential mode impedance. Because the differential signal quality (larger eye opening) is improved, data can be transmitted over a longer transmission line with the same transmitter and receiver.

A receiver receives an electromagnetic signal via an antenna mounted on an antenna mast. A signal evaluator determines or measures a signal quality level associated with the received electromagnetic signal. The signal quality compares the determined signal quality level to a threshold minimum signal quality level. A current elevational position of the antenna mast is detected or tracked. The antenna mast is raised to a greater height than the current elevational position if the compared signal quality level is less than the threshold minimum signal quality level and if the current elevational position is less than a maximum height of the antenna mast.

A predictive method and apparatus are disclosed for selecting an antenna to use in a multi-antenna wireless device. A predictive antenna selector predicts the best antenna (for both receiving and transmitting signals) based on the signal quality of the antenna for prior received frames. The quality of each antenna is evaluated, for example, in a random order, round robin fashion or according to some equal or weighted schedule. The signal quality can be evaluated for a given antenna during a preamble portion of a frame or for any frame up to an entire frame duration. A given antenna can be removed from the signal quality evaluation (for example, to a bad antenna list) if the given antenna fails to satisfy one or more predefined criteria, such as whether a signal quality of a given antenna is below a signal quality of a remainder of the plurality of antennas by a predefined amount. The signal quality of antennas on the bad antenna list can be reevaluated to determine when to return a removed antenna to the plurality of antennas that are evaluated.

A system having dualband power amplifier control in a dualband phone is provided using a single power amplifier controller. The dualband phone includes two power amplifiers, where each power amplifier amplifies the power of a signal transmitted at a different frequency band. A power amplifier controller is provided for controlling the amount of amplification performed by both of the power amplifiers, and a power amplifier switching device is connected to the power amplifier controller for switching the connection of the power amplifier controller between the two power amplifiers. The system further includes a processing device which monitors the quality and strength of the received signal transmitted by various base stations in the transmission region of the dualband phone. The processing device instructs the power amplifier switching device to switch its connection between the two power amplifiers based upon a determination of which frequency band provides the optimal balance between signal quality and signal strength, and the dualband phone then transmits its signal within the selected optimal frequency band. The system measures the power of the signal transmitted from the power amplifier connected to the power amplifier controller and feeds the measured power value back to the power amplifier controller, so that the power amplifier controller may adjust the voltage driving the power amplifier connected thereto based upon any differences found between the desired power output of the connected power amplifier and the measured power output.

A mobile device communicates with a first mesh access point (AP) via a first radio frequency (RF) interface of the mobile device over a first wireless connection, where the first mesh AP is one of mesh APs of a first mesh cell of the wireless mesh network. It is detected that signal quality of the first wireless connection drops below a predetermined threshold as the mobile device moves from the first mesh cell towards a second mesh cell. In response to the detection, it is established via a second RF interface of the mobile device a second wireless connection with a second mesh AP of a second mesh cell of the wireless mesh network, while concurrently maintaining the first wireless connection with the first mesh AP via the first RF interface.

A wireless signal repeater having an integrated display that concurrently displays a receive signal level, a transmit signal level, and a textual indication of signal quality, reflecting how well the repeater is currently operating to repeat wireless signals. By reference to the integrated display, a user can readily determine whether the repeater is well positioned to function as desired. And if the display indicates that the repeater is not functioning optimally, the user can then conveniently move the repeater around until the repeater reflects an acceptable level of operation.

A system and methods for permitting open access to data objects and for securing data within the data objects is disclosed. According to one embodiment of the present invention, a method for securing a data object is disclosed. According to one embodiment of the present invention, a method for securing a data object is disclosed. The method includes the steps of (1) providing a data object comprising digital data and file format information; (2) embedding independent data into a data object; and (3) scrambling the data object to degrade the data object to a predetermined signal quality level. The steps of embedding and scrambling may be performed until a predetermined condition is met. The method may also include the steps of descrambling the data object to upgrade the data object to a predetermined signal quality level, and decoding the embedded independent data. The additional steps of descrambling and decoding may be performed until a predetermined condition is met. The predetermined condition may include, for example, reaching a desired signal quality of the data object.

A method for ongoing power control for a communication station with a multiple antenna array, the power control using a method for signal quality estimation applicable for angle modulated signals. One aspect of the ongoing power control method is applicable for the uplink and includes separating the joint determination of a receive weight vector and ongoing power control into a receive weight vector determining part and a separate transmit power adjustment part. In one embodiment, the ongoing power control method for the downlink includes separating the joint determination of a receive weight vector and ongoing power control into a receive weight vector determining part and a separate transmit power adjustment part. The method starts with one part, for example transmit power assignment. Receive weight vector determination is carried out with this assigned transmit power, and the new weights used. An estimate of the resulting received signal quality is obtained and used for new ongoing power adjustment. Another aspect is applicable for the downlink and includes one aspect of the ongoing power control method is applicable for the uplink and includes separating the determination of a complete transmit weight vector including the vector of relative transmit weights and the scaling to use with the relative transmit weights into a part for determining a set of relative transmit weights and a separate transmit power adjustment part that determines the scaling factor.

The invention relates to a method for transmitting signals via a point-to-point microwave radio link from a transmitting unit 1, 2 to a receiving unit 2, 1 of a point-to-point microwave radio system, which signals comprise packets. In order to improve the efficiency on the radio link, it is proposed that in a first step, the packets are classified before transmission based on at least one quality of service parameter assigned to each packet. In a second step, the signals are modulated by the transmitting unit 1, 2 for transmission with a real-time adaptive modulation. This modulation is adapted based on the current traffic amount, on signal quality measurements indicative of the propagation conditions on the radio link, and on the classification of packets comprised in the signals. The invention relates equally to such a point-to-point microwave radio system comprising two units 1, 2 between which signals are to be transmitted, and to transmitting unit 1, 2 for such a system.

Method and apparatus for detecting possible interference in a neurological signal received from a monitoring element of a medical device system. The monitoring element monitors a condition or a symptom of a nervous system disorder being treated and provides a neurological signal to the medical device system for purposes of providing closed-loop feedback control. The system analyzes various parameters of the received signal by taking instantaneous measurements of data points in moving window and thereby determining whether the signal is of poor quality. If the signal is of determined poor quality, it is removed from consideration in the closed-loop feedback control system until it is determined that the signal quality has sufficiently been restored.

A method for controlling the transmission of data in a radio communications system transmits response signals from a receiver which includes information that reflects received signal quality, as well as information indicating whether an error has occurred in the data transmission. In one case, acknowledgment signals or negative acknowledgment signals may be regarded as no reply and not forwarded to a transmitter. In another case, the signals could be recognized as an acknowledgment or retransmission request by a receiver. Preferably, the signals transmitted from the receiver to the transmitter are composed of more than 2-bit multiplexed information. By transmitting response signals of this type, the transmission efficiency of packet data may be increased, and the automatic repeat request (ARQ) performance by the system may be greatly improved.

An antenna apparatus that can increase capacity in a wireless communication system is disclosed. The antenna operates in conjunction with a station and comprises a plurality of antenna elements, each coupled to a respective weight control component to provide a weight to the signal transmitted from (or received by) each element. The weight for each antenna element is adjusted to achieve optimum reception during, for example, an idle mode when a pilot signal is received. The antenna array creates a beam former for signals to be transmitted from the mobile station, and a directional receiving array to more optimally detect and receive signals transmitted from the base station. By directionally receiving and transmitting signals, multipath fading and intercell interference are greatly reduced. The weights are adjusted in a coarse and a fine mode. In the coarse mode all the weight control components are jointly adjusted or changed so that the antenna beam scans through a predetermined sector of a circle until a signal quality metric of the received signal is optimized. The coarse adjustment mode is followed by a fine adjustment mode during which the weights of are independently adjusted to further optimize the signal quality metric.

Aspects of a method and system for rate selection algorithm to maximize throughput in closed loop multiple input multiple output (MIMO) wireless local area network (WLAN) system are provided and may comprise computing a maximum number of binary bits to be simultaneously transmitted via an RF channel based on signal quality. A modulation technique may be selected based on the computed maximum, communicating feedback information comprising the selected modulation technique. Subsequently transmitted data may be received via an RF channel which is modulated based on the feedback information. Another aspect of the method may comprise receiving feedback information comprising at least one of a selected modulation technique and coding rate via an RF channel, and transmitting subsequent data via said at least one of a plurality of RF channels which either modulated, or coded, based on the feedback information.

A system and method may use mm-wave superspots to download high volumes of data to a moving or stationary mobile device traveling along a travel route that the moving mobile device is traveling. A macrocell in communication with the mobile device may predict the route that the mobile device is traveling, such as via GPS location, moving speed and direction, map information, etc. Alternatively, the route being taken may be determined by wireless communication, such as between the mobile device and a macrocell and/or superspot. The macrocell and/or superspot may determine whether (1) there are any mm-wave superspots along the predicted or known route that the mobile device is taking; (2) there is any data that is requested or remaining to download to the moving mobile device; and/or (3) the received signal quality, channel conditions, and/or macrocell traffic to the mobile device are favorable for superspot downloading.

A method of registering distributed devices includes discovering a plurality of devices at a central panel or server, localizing the devices, and authorizing the devices with a mobile device communicating with the central panel or server. The method also includes registering the devices with the central panel. The model can include verifying link quality with each of the devices before registering the devices with the central panel by comparing signal quality between each device and a central panel with a pre-defined threshold level.

An input signal enters a noise suppression system in a time domain and is converted to a frequency domain. The noise suppression system then estimates a signal to noise ratio of the frequency domain signal. Next, a signal gain is calculated based on the estimated signal to noise ratio and a voicing parameter. The voicing parameter may be determined based on the frequency domain signal or may be determined based on a signal ahead of the frequency domain signal with respect to time. In that event, the voicing parameter is fed back to the noise suppression system, for example, by a speech coder, to calculate the signal gain. After calculating the gain, the noise suppression system modifies the signal using the calculated gain to enhance the signal quality. The modified signal may further be converted from the frequency domain back to the time domain for speech coding.

Method and apparatus for detecting possible interference in a neurological signal received from a monitoring element of a medical device system. The monitoring element monitors a condition or a symptom of a nervous system disorder being treated and provides a neurological signal to the medical device system for purposes of providing closed-loop feedback control. The system analyzes various parameters of the received signal by taking instantaneous measurements of data points in moving window and thereby determining whether the signal is of poor quality. If the signal is of determined poor quality, it is removed from consideration in the closed-loop feedback control system until it is determined that the signal quality has sufficiently been restored.

In an OFDM packet communication receiver, the deterioration of received signal quality is suppressed, even when carrier frequency error and/or clock frequency error exists between a transmitter and a receiver, and/or phase noise and/or thermal noise is superimposed to a received signal in a receiver.

A method and apparatus for determining operating modes in a receiver is described herein. A delay searcher in the receiver detects a signal image in the received signal. When the receiver is a RAKE receiver, a plurality of RAKE fingers coherently combine time-shifted versions of the received signal at different delays. Alternatively, when the receiver is a chip equalization receiver, an FIR filter coherently pre-combines the signal images in the received signal. A processor determines delays. In particular, the processor generates a first signal quality metric for a single-delay receiver mode, and generates a second signal quality metric for a multi-delay receiver mode. Based on a comparison of the first and second signal quality metrics, the processor selects the single-delay or the multi-delay receiver mode for processing the signal image.

In a wireless network system having a wired backbone network with two or more sub-networks, each having one or more access points for communicating with wireless units via a wireless transmission medium, a system, apparatus and method for a wireless unit to determine whether a candidate access point is on a different sub-network than its current access point. If the wireless unit determines that the candidate access point is on a different sub-network, then the wireless unit releases its current network protocol address which was valid for the current sub-network, and obtains a new network protocol address valid for the new sub-network. This is accomplished by the candidate access point transmitting a multicast packet that includes the network protocol address of the access point and the subnet mask of the sub-network which the access point is on. By receiving this multicast packet, the wireless unit can determine if the candidate access point is on a different sub-network than its current sub-network. Also disclosed is a technique for a wireless unit to determine whether to roam to a candidate access point based on the signal qualities to its current and candidate access points, and whether the candidate access point is on a different sub-network or a designated restricted sub-network.

A package-board co-design methodology preserves the signal integrity of high-speed signals passing from semiconductor packages to application PCBs. An optimal architecture of interconnects between package and PCB enhances the signal propagation, minimizes parasitic levels, and decreases electromagnetic interference from adjacent high frequency signals. The invention results in devices with superior signal quality and EMI shielding properties with enhanced capability for carrying data stream at multiple-gigabit per second bit-rates.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

A signal processing system detects reverberation. The system may suppress the reverberation and improve signal quality. The system analyzes frequency bands of an input signal to determine whether reverberation characteristics are present. When reverberation is detected, the system may attenuate the reverberant frequency band to reduce or eliminate the reverberation.