6867 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 data confidence indicator includes a plurality of physiological data and a plurality of signal quality measures derived from a physiological sensor output, and a plurality of comparator outputs each responsive to one of the measures and a corresponding one of a plurality of thresholds. An alert trigger output combines the comparator outputs. A low signal quality warning is generated in response to the alert trigger output, wherein the thresholds are set so that the warning occurs during a time period when there is low confidence in the data. The alert may be in the form of a message generated on the pulse oximeter display to warn that the accuracy of saturation and pulse rate measurements may be compromised. A confidence-based alarm utilizes signal quality measures to reduce the probability of false alarms when data confidence is low and to reduce the probability of missed events when data confidence is high.

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 lidar-based apparatus and method are used for multi-signal detection, weak signal detection and signal disambiguation through waveform approximation utilizing a multi-channel time-to-digital converter (TDC) electronic circuit, with each TDC having an individually adjustable voltage threshold. This advanced TDC-based pulse width time-of-flight (ToF) approach achieves the low cost associated with the TDC-based pulse width ToF approach while solving the signal quality issues associated with the standard single-threshold TDC-based approach.

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.

A system and method for gathering and reporting user and device activity data from wireless communication devices through a log file. The log file stores entries related to user events including the use of communications and applications, as well as access to local and remote media resource files. The log file entries may include parameters critical to mobile device operation such as location, signal quality, and battery power. The data gathering system comprises a plurality of wireless communications devices, each of which sends the log files through an available wireless communications system to a central facility for processing and aggregation into a database. Stored data is analyzed to generate, display, and marketing information that may include historical trends and projections of future consumer preferences and activities.

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 receiver circuit suppresses effects of “benign” impairment from the calculation of received signal quality estimates, such that the estimate depends primarily on the effects of non-benign impairment. For example, a received signal may be subject to same-cell and other-cell interference plus noise, which is generally modeled using a Gaussian distribution, and also may be due to certain forms of self-interference, such as quadrature phase interference arising from imperfect derotation of the pilot samples used to generate channel estimates for the received signal. Such interference generally takes on a distribution defined by the pilot signal modulation, e.g., a binomial distribution for binary phase shift keying modulation. Interference arising from such sources is relatively “benign” as compared to Gaussian interference and thus should be suppressed or otherwise discounted in signal quality calculations. Suppression may be based on subtracting benign impairment correlation estimates from total impairment correlation estimates, or on filtering the benign impairment in channel estimation.

The present invention relates to a method and system for transmitting a transmission signal from an antenna array (19) to a receiving means (20) of a wireless communication system, wherein a signal quality measurement is performed at the receiving means (20) for predetermined antennas or beams of said antenna array (19). Based on a feedback information derived from the signal quality measurement, at least two of the predetermined antennas or beams of the antenna array (19) are selected. The selected antennas or beams are used for transmitting said transmission signal according to a transmit diversity or beamforming scheme. Thus, spectral efficiency and diversity gain can be enhanced by using only selected ones of the predetermined antennas or beams.

A method for power control with signal quality estimation for smart antenna communications system is described. The method, for example, starts with a 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 another power adjustment.

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.

Methods and systems for enabling the rectification of deteriorated channel conditions on a communication link are described. In particular, the methods and systems can employ mechanisms that prioritize beams in accordance with signal quality measures, direction of departures of transmission beams and / or direction of arrivals of reception beams to address variable channel conditions.

A redundently modulated multicarrier protocol known as Carrier Interference Multiple Access (CIMA) is used in an optical-fiber network having wireless links at network nodes. CIMA is a protocol that can be used to create wireless protocols (such as TDMA and CDMA) having enhanced capacity and reduced system complexity. A CIMA optical-fiber network uses dispersion to enhance signal quality and facilitate switching. CIMA achieves both diversity benefits and capacity enhancements by providing redundancy in at least one diversity parameter while providing orthogonality in another diversity parameter. This basic operating principle of CIMA may be combined with multi-user detection to achieve frequency reuse and improved power efficiency. In the wireless link, diversity may be used to reduce the effects of small-scale fading on interferometry multiplexing.

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.

Packets are routed in a wireless mesh network by assigning a probability of packet retransmission based on certain factors which may include the number of hops the packet has made, whether the destination is within a certain number of known hops of the receiving node, the number of nearby nodes, whether the receiving node is a member of a past known route to the destination and / or whether a nearby neighbor of the receiving node is a member of a past known route to the destination. Once a probability is assigned, a random number generator may be used to make a decision between retransmitting the packet and dropping the packet. Signal quality may also be used as a factor in the probability of retransmission. In a preferred embodiment, Bloom filters are used to store information in the header of a data packet containing the identifiers of forwarding nodes and the identifiers of nodes on a previously-successful route from the source to the destination.

A system for managing the operation of a plurality of radio modules integrated within the same wireless communication device. In at least one embodiment of the present invention, a control strategy may be employed to regulate the quality level of a signal delivered by a codec in order to balance the performance realized in the reproduction certain signals with overall communication stability in the wireless communication device. The regulation of signal quality level may be affected by reducing the bit rate of a codec, changing the codec to select another codec with a lower bit rate, or by performing bitrate scaling with the codec signal.

An adaptive beam-forming system using hierarchical weight banks for antenna arrays in wireless communication systems is disclosed. The present invention can be applied for both reception and transmission beam-forming. The hierarchical weight banks contain weights that are pre-calculated based on pre-set beam look directions. By comparing measurements of chosen signal quality metrics for pre-set look directions, the best weights, and thus the best beam look direction, can be selected from the weight banks.

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.

Described embodiments provide a method and apparatus for redirecting user equipment from a current serving cell of a first network to a corresponding target cell of a second network in a heterogeneous overlay network environment. A current serving base station of the first network may receive signal quality measurements from user equipment coupled to the current serving cell of the first network. Based on the received signal quality measurements, the current serving base station may determine whether signal quality of the user equipment is lower than predetermined reference quality based on at least one of the received signal quality measurements. When the signal quality of the user equipment is lower than the predetermined reference quality, the current serving base station may redirect the user equipment from the current serving cell of the first network to the corresponding target cell of the second network.