3495results about "Synchronisation signal speed/phase control" patented technology

A system, method and program are disclosed for achieving rapid bit synchronization in low power medical device systems. Messages are transmitted via telemetry between a medical device and a communication device. The synchronization scheme uses a portion of a unique preamble bit pattern to identify the communication device allowing for economical communications with a minimum expenditure of energy. A special set of preamble bit patterns are utilized for their unique synchronization properties making them particularly suited for rapid bit synchronization. These unique preamble bit patterns further provide simplification to the preamble error detection logic.

A method and an apparatus for performing synchronization by a first device in a Device-to-Device (D2D) network are provided. The method includes detecting a synchronization signal from at least one second device during one period, determining a phase adjustment value depending on a number of synchronization signals, which have been detected from the at least one second device during the one period, adjusting a phase value of a first device using the phase adjustment value, and transmitting a synchronization signal if the phase value of the first device reaches a predetermined specific value.

Two electronic devices automatically perform a synchronization session when one of the electronic devices is brought in proximity to the other electronic device. The synchronization session is initiated without user intervention based simply on the fact that the two devices have recently been brought within a predetermined distance of each other. The two electronic devices communicate in a wireless manner. The two devices may determine that they are within a predetermined distance of each other using global positioning technology, via which one of the devices determines its own position and compares it to a known position of the other electronic device. Alternatively, one of the electronic devices may output a low level signal that can be received by the other electronic device when within a certain range. Once the low level signal is received, the recipient of the low level signal outputs a stronger signal to ensure that it is received by the other electronic device requesting a synchronization session, which once established enables synchronization of information between the two devices.

A near field RF communicator has: an antenna operable to generate an RF signal to enable inductive coupling via the magnetic field of the RF signal between the antenna and another near field RF communicator or RF transponder in near field range; and a signal generator operable to generate a multi-level digital sine wave drive signal to drive the antenna to generate the RF signal, wherein the signal generator comprises a selector operable to select one or more digital sequences to provide one or more digital signals from which the digital sine wave drive signal is generated.

A wireless communication system can comprise two or more antennas that interfere with one another via free space coupling, surface wave crosstalk, dielectric leakage, or other interference effect. The interference effect can produce an interference signal on one of the antennas. A cancellation device can suppress antenna interference by generating an estimate of the interference signal and subtracting the estimate from the interference signal. The cancellation device can generate the estimate based on sampling signals on an antenna that generates the interference or on an antenna that receives the interference. The cancellation device can comprise a model of the crosstalk effect. Transmitting test signals on the communication system can define or refine the model.

An apparatus and method to synchronize devices in a network to a sub-millisecond timing accuracy. In a first embodiment, the transmission of data is synchronized between a first source device and destination devices communicatively coupled to a network. In a second embodiment, data is deterministically transmitted between a first source device and destination devices communicatively coupled to a network. In a third embodiment, a deterministic network synchronizes the transmission of data between a first source device and destination devices coupled to a network.

Timing synchronization between base stations of uncoordinated communication networks includes obtaining timing synchronization information from one base station, and adjusting a clock of the other station in response to the synchronization information. The timing synchronization information can be identified from a strongest synchronization signal from nearby uncoordinated base stations. The timing synchronization can accommodate clock offsets and frequency offsets.

Systems and methods are disclosed for time synchronization of operations in a control system. Synchronization networks and devices are provided for transferring synchronization information between controllers in a distributed or localized control system, which is employed in order to allow operation of such controllers to be synchronized with respect to time. Also disclosed are synchronization protocols and hardware apparatus employed in synchronizing control operations in a control system.

A method is provided for synchronizing the playback of a digital audio broadcast on a plurality of network output devices by inserting a control track pulse in an audio stream of the digital audio broadcast. The method includes the steps of outputting a first control track pulse as part of an audio signal which has unique identifying characteristics and is regularly occurring, outputting a second control track pulse so that the time between the first and second control track pulses must be significantly greater than the latency between sending and receiving devices, and coordinating play of audio at the time of the occurrence of the transmission of the second control track pulse assuring the simultaneous output of the audio signal from multiple devices. The control track pulses have a value unique from any other portion of the audio stream. The digital audio broadcast from multiple receivers does not present to a listener any audible delay or echo effect.

Signal construction, detection and estimation techniques for use in uplink timing synchronization and access control in an orthogonal frequency division multiplexed (OFDM) wireless system or other type of wireless communication system. In accordance with an illustrative embodiment of the invention, timing and access signals to be transmitted in designated timing and access intervals are constructed from orthogonal multitone signals. The multitone signals may be similar to multitone signals used in OFDM data transmission, except that a cyclic prefix associated with reception of the signals in a base station is extended to cover the timing errors of mobile stations not yet synchronized. The invention also provides design techniques which optimize the time resolvability and peak-to-average ratio of the multitone signals, an efficient fast Fourier transform (FFT) based technique for maximum likelihood timing estimation, and a robust linear filtering technique for averaging timing estimates from different synchronizations.

This invention describes a wireless system comprising a plurality of transmitters and receivers, wherein each transmitter has between 1 and n antennas and each receiver has between 1 and m antennas wherein one of said transmitter is arranged to transmit to one of the receivers, said one transmitter is controlled in dependence on at least one of at least one parameter of said transmitters, at least one parameter of said receiver, and at least one parameter of a wireless environment between said transmitter and said receiver.

A data Interface for transferring digital data between a host and a client over a communication path using packet structures linked together to form a communication protocol for communicating a pre-selected set of digital control and presentation data. The signal protocol is used by link controllers configured to generate, transmit, and receive packets forming the communications protocol, and to form digital data into one or more types of data packets, with at least one residing in the host device and being coupled to the client through the communications path. The interface provides a cost-effective, low power, bi-directional, high-speed data transfer mechanism over a short-range “serial” type data link, which lends itself to implementation with miniature connectors and thin flexible cables which are especially useful in connecting display elements such as wearable micro-displays to portable computers and wireless communication devices.

A radio frequency (RF) motion capture system includes stationary sensor receivers, one or more transmitter marker tags on one or more objects to be tracked within a capture zone, at least one stationary reference tag transmitter, and a processing system for processing the received signals. The individual tags transmit burst of spread-spectrum RF signals. The transmitted signals include a common sync code, and a tag identification code that is unique to each tag. By computing double differences of pseudoranges, clock terms are cancelled out allowing the processing system to precisely determine the location of each tag as it moves through the capture zone without the need to synchronize clocks between sensors and tags. The system can be used for RF match moving.

A wireless spread spectrum communication system for transmitting data includes a plurality of end point transmitters and at least one receiver. The end point transmitters transmit data via a frequency hopped spread spectrum signal where the transmitting signal is sent without the benefit of frequency stabilization. The receiver is responsive to the frequency hopping spread spectrum signals and includes a correlator and a signal processor. The correlator samples at least a first portion of a preamble of the signal and correlates the portion of the preamble with a known preamble pattern to determine a probability of correlation. The signal processor applies a Fast Fourier Transform algorithm to the signal in response to the probability of correlation to track a narrowband frequency of the signal based on at least a second portion of the preamble and to decode data encoded within the signal subsequent to the preamble.

An improved method of processing random access procedures, wherein the network receives at least one access burst to allow a network to estimate uplink received timing, the access burst containing at least a preamble, and transmits information for responding to the at least one access burst, while the mobile terminal configures at least one access burst containing at least a preamble and transmits the at least one access burst to allow a network to at least estimate uplink received timing.

A method for coexistence radio communication systems is presented. In one embodiment, the method includes receiving a realtime frame synchronization signal and receiving one or more frame parameters. The method further includes determining, based at least on the frame synchronization signal and the frame parameters, estimated frame timing information and scheduling transmission based on the estimated frame timing information to avoid collision of the transmission and reception.

Method and apparatus for OFDM synchronization and channel estimation. In a temporal embodiment, received embedded system pilot symbols are inverse Fourier transformed at expected index locations and correlated with computed complex conjugates of inverse Fourier transforms of pilot symbols for providing a correlation function for the channel impulse response. In a frequency domain embodiment, embedded system pilot symbols are augmented with pilot-spaced inferred guard band symbols, multiplied by scaled complex conjugates of computed pilot systems, and inverse Fourier transformed into the channel impulse response. Time and frequency are synchronized in feedback loops from information in the channel impulse response. The channel impulse response is filtered, interpolated, and then Fourier transformed for determining channel estimates for equalization.

Methods and an arrangement for synchronizing communication of framed data via asynchronous base stations (BS1, BS2) in a cellular communication system are presented. The synchronization methods are performed continuously by sending out certain system frame counter states from a central node in the system to all its connected base stations (BS1, BS2). Each base station (BS1, BS2) includes a local frame counter (LFCBS1, LFCBS2), which generates local frame counter states (t1(1)-t1(4), t2(1)-t2(4)) correlated to the system frame counter states. Transmission of information via the base stations (BS1, BS2) is synchronized by assigning each data frame (DR(1)-DR(4)) a particular frame number, which is given by the local frame counter states (t1(1)-t1(4), t2(1)-t2(4)), so that data framed (DF(1)-DF(4)) having identical numbers contain copies of a certain data packet. Correct frame numbers are derived from common downlink channel offset measurements (CCO1, CCO2) carried out in the base stations (BS1, BS2), and timing advance values (TA2) and downlink channel offsets (DCO1, DCO2) calculated in the central node.

A direct sequence spread spectrum receiver samples an incoming signal and translates the signal to an IF signal. The IF signal is sampled and stored in memory. In one embodiment, the memory consists of two memory banks which alternately receive sample segments. During a write period to one of the memory banks, the other memory bank supplies its output to a processor. This continues in a ping-pong manner. In another embodiment, a single memory bank is filled and read as necessary, the receiver ignoring incoming signal until the processor has completed processing the sample available at the output of the memory. Such a receiver is useful in global positioning satellite (GPS) signal processing where the incoming signal contains several satellite transmissions encoded with CDMA encoding.

A method and apparatus for detecting and synchronising packets of data with a repeated sequence as a pilot symbol received by a communications system are provided. The method and apparatus include receiving data, detecting a packet within the received data, producing an estimate of the time-varying frequency offset of the received data, estimating the start of the packet of the received data, estimating the time-varying phase offset of the received data and estimating the time-varying time offset of the received data. Methods for assessing each one of the time-varying frequency offset, the time-varying phase offset, the time-varying time offset and the start of packet are also provided.