Abstract: A synchronization timing detecting apparatus includes a correlation calculator configured to generate a first correlation value by calculating a cross-correlation between an input signal being sampled and a reference signal or an auto-correlation of the sampled input signal, an interpolation processor configured to generate a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal, and a detector to detect a synchronization timing based on the first and the second correlation values.

Abstract: Synchronization techniques for reducing the effects of time dispersive wireless communications channels are presented. A synchronization technique for communications over a time dispersive wireless channel includes receiving a signal having at least identical first and second symbols, and calculating a metric for each sampling time by correlating respective samples of the first symbol included in a first sampling window with respective samples of the second symbol included in a second sampling window. The technique further includes identifying one of the sampling times at which the metric attains a maximum value, and estimating an optimal time offset for synchronizing to the received signal based on the identified sampling time. Optionally, the technique further includes estimating a carrier frequency offset based on the difference of phase of the complex conjugate samples at the maximum absolute value of the metric.

Abstract: Methods and apparatuses for dynamically adjusting sync windows are described. A default sync window is set; a data signal is input; detecting if parts of the data signal within the sync window form a sync pattern; accumulating a count of the sync pattern within and without the sync window; and reducing the sync window when the count of sync pattern within the sync window achieves a first threshold value, and increasing the sync window when the count of the sync pattern outside the sync window achieves a second threshold value.

Abstract: A time domain symbol timing synchronization circuit is disclosed, which comprises: an autocorrelation function calculator for calculating cyclic prefix autocorrelation functions and an offset time estimator for searching peak positions of cyclic prefix autocorrelation functions to indicate symbol boundary of received communication symbols. The offset time estimator compares a current peak position and a previous peak position. If (a) the difference of the positions is larger than a threshold and (b) the current peak is smaller than a reference average peak, the current peak is determined as false; the offset time estimator weeds out and replaces the current peak position by the previous peak position; and the current peak is not introduced in the reference average peak calculation.

Abstract: A circuit includes: a portion for performing a logical operation based on a binary modulated signal and a cyclic signal; serial-to-parallel converter for sampling a operation output for parallel output; correlation filter having multiple digital filters for allowing the parallel signal values to pass therethrough; maximum difference detector for detecting a maximum difference in a period during which a difference between the maximum and minimum output signal values from digital filters is greater than a threshold; timing detector for detecting the inversion timing of each output signal value; and decision timing exterminating portion for determining decision timing based on the maximum difference and the detected inversion timing.

Abstract: The present invention relates to a method for synchronization of real-time signals between core network and air interface in a UMTS Terrestrial Radio Access Network (UTRAN). The synchronization of the signals is needed to make a feasible connection between user equipment and a core network. This is achieved by using the timing knowledge from the protocols that are to be synchronized, and recalculating synchronization parameters for both uplink and downlink transmission. By using frame numbers instead of time of arrivals of frames, the present invention gives better control of timing and avoids long delays, and handles the problems with time alignments.

Abstract: A method is provided for receiving a data frame in an ultrawide bandwidth network. In this method, a device receives an ultrawide bandwidth signal containing a data frame. The device then performs an acquisition operation during a first preamble in the data frame, and identifies a marker after the first preamble that indicates that the first preamble has ended. After this, the device performs a signal processing operation during a second preamble in the data frame. After the training, the device then receives a header in the data frame, and then receives a payload in the data frame. By having a marker between the two preambles, this method provides a receiving device with critical information regarding the timing of the preamble section of a frame.

Abstract: 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.

Abstract: A frame synchronization method is disclosed. The method comprises correlating a stream with a pattern to generate a correlated result c(t). A first peak and a second peak are selected from the correlated result c(t), wherein the first peak is the peak with highest amplitude, and the second peak is the peak occurring later than the first peak with the second highest amplitude. The peak ratio of the two peaks is computed, and the position of the frame boundary is determined according to the ratio.

Abstract: A pilot structure, a method, and a receiver for multi-carrier cellular communications defining a specific Time Division Multiplexer/Multiplexing pilot pattern and pilot sequence for a sub-frame with short system information. A primary synchronization sequence is configured to be transmitted every predetermine number of sub-frames in a defined bandwidth. A primary common pilot is configured to be transmitted for each sub-frame. Short system information is configured to be transmitted once per frame to define the pilot structure of sub-frames in a frame period to define a structure of a frame period.

Abstract: A method of synchronizing a base station of a wireless communication system and a subscriber communication equipment located in the coverage area of the base station by compensating a sampling frequency offset in the subscriber equipment by interpolating input and/or output signals of a radio frequency part of the communication equipment to generate samples corresponding to the original symbol timing of the base station, and compensating the carrier frequency offset from the estimate of the sampling clock error.

Abstract: A wireless communication apparatus comprises a transmission buffer configured to store packets addressed to one or more communication nodes in the network until a transmission timing; a requesting interval determination unit configured to determine a listen interval for each of the communication nodes based on the amount and/or the priority of packets accumulated in the transmission buffer; and a transmission unit configured to transmit a request frame to each of the communication nodes to request the communication nodes to receive a beacon from the wireless communication apparatus at the determined listen interval.

Abstract: An apparatus and method are described for synchronizing distribution of packet information. In one embodiment, the invention includes timestamp processing logic to process a transmit time indicator embedded within the packet information, where the transmit time indicator is based on a time reference, and service synchronization queuing logic to hold the packet information until a time offset after the transmit time indicator, where the service synchronization queuing logic is synchronized to the time reference.

Abstract: A Bluetooth master unit polls a slave unit to enable the slave to resynchronize to the master, by sending POLL packets with sufficient frequency to maintain a connection to the slave, and in the intervals between such packets, sending NULL packets with sufficient frequency to maintain synchronization of the slave. By replacing some POLL packets with NULL packets, since the slave does not have to respond to a NULL packet, it can save some power, and there is reduced interference on other piconets. The frequency of the remaining POLL packets is set according to a Link Supervision Timeout (to avoid having this timer expire and thus keep the Bluetooth Link to the slave alive) and according to the time since the master received the last packet from the slave.

Abstract: Disclosed is a random access data transmission system and method using OFDMA. The system includes a scheduling ID into an access grant on a preamble for a random access, and transmits it together with an acknowledgment or a non-acknowledgment of the preamble, a base station uses the scheduling ID to notify the mobile station of a random access data transmittable time and a data transmission channel through a control channel, and the mobile station transmits a preamble in advance. After receiving a transmission assignment instruction corresponding to a scheduling ID through the control channel, the mobile station transmits random access data through an assigned channel.

Abstract: A double data rate SMII circuit comprises a transmit circuit, responsive to a clock signal, that samples serial transmit data on a clock rising edge to generate a first transmit serial stream. The transmit circuit, responsive to the clock signal, samples the serial transmit data on a clock falling edge to generate a second transmit serial stream. A receive circuit, responsive to the clock signal, generates a receive serial stream from two receive data streams. The receive serial stream having a first operating frequency, each of the two receive data streams having a second operating frequency. The first operating frequency is about twice the second operating frequency. A transmit port, corresponding to the transmit circuit, includes a single terminal to communicate the serial transmit data to the transmit circuit. A receive port, corresponding to the receive circuit, includes a single terminal to communicate the receive serial stream from the receive circuit.

Abstract: Disclosed is a method for synchronizing a bitstream, the method comprising comparing an incoming data byte of the bitstream with a predetermined byte pattern; writing a result of the comparison to a current write address in a FIFO; calculating a difference between a current read address in the FIFO and the current write address; asserting a synchronization signal when the difference equals a predetermined value; the result of the comparison is asserted; and an output of the FIFO at the current read address is asserted.

Abstract: A receiver in an OFDM system may include a joint maximum likelihood (ML) estimator that estimates both time offset and frequency offset. The estimator may use samples in an observation window to estimate the time offset and frequency offset.

Abstract: Detecting a boundary within a transmitted packet is disclosed. A first symbol of the transmitted packet is received in a band. A second symbol of the transmitted packet is received in the band. The first and second symbols are compared. The boundary within the transmitted packet is detected based at least in part on the comparison of the first symbol and the second symbol and the band.

Abstract: Embodiments of methods and apparatus for providing a delayed attack protection system for network traffic are generally described herein. Other embodiments may be described and claimed.

Abstract: A method of processing data comprises the receiving a frame of data having a predetermined number of time slots (502,504,506). Each time slot comprises a respective plurality of data symbols (520). The method further comprises a primary (508), a secondary (510) and a tertiary (512) synchronization code in each said predetermined number of time slots.

Abstract: Transmission of broadcast streams in multiple sectors is synchronized based on time stamps or sequence numbers in data packets received at the base station. The base stations use the time stamps to calculate a frame transmission start time and start position for the data packets. The base station monitors the packet latency of data within its buffer based on the time stamp in the data packets and initiates a resynchronization procedure if the packet latency exceeds predetermined bounds.

Abstract: A centralized clock distribution mechanism for synchronous TDM communications traffic transported over asynchronous networks such as Ethernet networks. The centralized clocking mechanism of the present invention distributes a high accuracy central clock source to a plurality of CES modules over an Ethernet network. Clock synchronization information based on a high quality clock reference source is distributed to circuit emulation service (CES) modules in the network. CES modules receive the clock synchronization information and use it to reconstruct a local clock. A plurality of clock distributors provide clock redundancy whereby each CES module selects the best clock source to use in reconstructing the local clock.

Abstract: An enhanced 8-VSB reception system and E8-VSB data demultiplexing method, by which an E8-VSB signal can be stably received as well as a previous ATSC 8VSB signal, is disclosed. Herein, the enhanced data are coded at ½ code rate and ¼ code rate in the new E8-VSB transmission system compatible with the conventional ATSC 8VSB system, respectively. The ½ and ¼ enhanced data are multiplexed by 164-byte packet unit according to the previously determined multiplexing format and further pre-processed to output as the format of the MPEG transport packet. And, the pre-processed enhanced data and the main data are multiplexed again by 188-byte packet unit according to the previously determined multiplexing format. The E8-VSB map information, which was inserted in the field sync section in the E8-VSB transmission system to be transmitted, is extracted to generate the information indicating the attributes of the respective E8-VSB data.

Abstract: A method of synchronizing an Orthogonal Frequency Division Multiplexed (OFDM) IEEE 802.11a data packet at a receiver is disclosed. The 802.11a data packet has a series of short training sequence (STS) symbols as a preamble. Cross-correlation at the receiver of the STS in the 802.11a packet PLCP preamble with the modified reference STS, that is 10 circular shifted by eight samples, results in a main correlation peak but with reduced pre- and post-lobes. To locate the cross-correlation peak, a running second derivative of the cross-correlation function is performed. Peak selection employs a running comparison of the position and magnitude of all peaks in the intermediate neighborhood of the local peaks. Following selection of a peak from within the cross-correlation function of the first STS in the PLOP preamble, both the position and magnitude of the first STS is compared to those of the second STS. Based on the two independent calculations, the start of the OFDM frame is estimated.

Abstract: A time division duplex (TDD) user equipment (UE) is configured to synchronize to a TDD base station. The UE includes a receiver configured to receive a primary synchronization code along with a plurality of secondary synchronization codes from a TDD base station. The TDD base station is associated with having a code group out of N code groups. The plurality of secondary synchronization codes number less than (log2N)+1 and are quadrature phase shift keying modulated. The UE also includes a corresponding matched filter to each of the received secondary synchronization codes. The UE is configured to identify the code group of the TDD base station by the received plurality of secondary synchronization.

Abstract: A time control mechanism accepts samples of time (true or otherwise) over a network, and enables dynamic compensation for random delays of the network in order to maintain the output of a slave clock that the time control mechanism controls within required bounds relative to the time of a master clock, even when the samples are randomly delayed. In one embodiment, a hardware timestamping method and apparatus is provided. The hardware timestamping method and apparatus is used to achieve the fine resolution required for timestamping both received samples and transmitted requests. In another embodiment, a delay-variation-smoothing method and apparatus is provided. The delay-variation-smoothing method and apparatus allows the time control mechanism to calculate the network delay in order to maintain the slave clock within the required time bounds.

Abstract: A wireless terminal using OFDM signaling supporting both terrestrial and satellite base station connectivity operates using conventional access probe signaling in a first mode of operation to establish a timing synchronized wireless link with a terrestrial base station. In a second mode of operation, used to establish a timing synchronized wireless link with a satellite base station, a slightly modified access protocol is employed. The round trip signaling time and timing ambiguity between a wireless terminal and a satellite base station is substantially greater than with a terrestrial base station. The modified access protocol uses coding of access probe signals to uniquely identify a superslot index within a beaconslot. The modified protocol uses multiple access probes with different timing offsets to further resolve timing ambiguity and allows the satellite base station access monitoring interval to remain small in duration.

Abstract: A network element for incorporating in nodes of a network that is a transparent, subwavelength networks. The element is configurable and adapted to support an arbitrary protocol, with protocol-specific monitoring features as well as protocol-independent add/drop capability. An arrangement that allows transmission of client signals with higher clock fidelity is achieved by developing a phases offset measure at an ingress node, communicating it to the egress node, and recovering the client's clock from the received data and from the received phase-offset information. The ability to recover the client's clock with high fidelity is enhanced by modified pointer processing in intermediate nodes of the network that the client's signal traverses. The pointer processing is modified to inject positive and negative justifications in excess of what is minimally necessary to insure proper transmission over a network that employs a protocol involving framing layer frames embedded in communication layer frames.

Abstract: The invention relates to a method of synchronizing first and second digital signals presenting digital elements to be put into correspondence, on the basis of time references. The method includes preliminary synchronization of the two digital signals using time references, by putting time references recognized as having the same value in the first and second digital signals into correspondence; and fine synchronization on the basis of a characteristic parameter obtained from the binary streams of the digital elements, and computed for each of the first and second digital signals.

Abstract: A method and system to synchronize a first device and a second device includes generating a first tone by the first device, the first tone one of including an identity of the second device and generated at a predefined time, receiving the first tone by the second device, setting a clock of the second device based on the received first time, and sending an acknowledgment by the second device to the first device.

Abstract: A wireless communications system in which an access point (AP) transmits a downlink signal for reception by one or more subscriber unit(s) (SU) and the subscriber unit (SU) transmits an uplink signal for reception by the access point (AP). The downlink signal from the access point (AP) carries syncronisation bursts (2) at predetermined times and data contained in frames interleaved between the synchronisation bursts. Each synchronisation burst comprises an offset pointer (4) to the start of the subsequent downlink frame.

Abstract: A method, apparatus, and system for sending and receiving notification messages to synchronize notification messages with program streams accurately. The method for sending notification messages includes obtaining a notification message and a synchronization timestamp that are synchronous with a program, encapsulating the notification message into an RTP/RTCP packet corresponding to the synchronization timestamp, and sending the RTP/RTCP packet to a terminal. The method for decapsulating notification messages includes receiving an RTP/RTCP packet that carries a notification message and decapsulating the RTP/RTCP packet to obtain the notification message. Embodiments of the present disclosure synchronize a notification message with a program stream accurately by carrying the notification message in an RTP/RTCP packet.

Abstract: The invention relates to a method of synchronizing a mobile station with a base station in a wireless communications system, to a mobile station for a wireless communications system, as well as to a wireless communications system of this kind. In order to enable faster ultimate synchronization, it is proposed to compare components of the received data not only with a stored synchronization pattern, but also with a stored identification pattern prior to the adaptation of the timing of the mobile station to received data. Already before the synchronization it can thus be determined with a high degree of probability whether received data originates from a desired base station or not. The necessity of checking the contents of packets which are not associated with a desired base station can thus be avoided.

Abstract: In one embodiment, a 10 Giga-bit Ethernet conversion system is provided that is operable to be inserted in 10 Gigabit optical fiber Ethernet systems, wherein each optical fiber Ethernet system includes an electrical-to-optical interface presenting electrical signals to an optical interface for converting the electrical signals to optical signals, the electrical signals being organized into a plurality of channels, wherein each channel carries Ethernet idle characters between data frame transmissions.

Abstract: A trigger signal generating apparatus includes a frame synchronous circuit which receives a frame signal having a predetermined bit rate and outputs a synchronous signal in synchronism with an input timing of leading data of the frame signal, a position information output circuit which receives the synchronous signal output by the frame synchronous circuit and outputs the position information indicating an input bit position of the frame signal, a position designator which designates an arbitrary bit position of the frame signal, and a trigger signal generating circuit which outputs a trigger signal at a timing when the position information output by the position information output circuit is coincident with the arbitrary bit position designated by the position designator. A trigger is generated accurately at an arbitrary bit position of the frame position.

Abstract: A network terminal of the present invention includes: a synchronization information frame receiving section for receiving a synchronization information frame from a master terminal; a network information managing section for maintaining the network by being synchronized with the synchronization information frame; a synchronization information frame missing detection section for detecting the missing of the synchronization information frame from the master terminal; a priority list storing section for storing a priority list which defines a synchronization information frame transmission start time in such a manner as to differentiate synchronization information frame transmission start times between the network terminals; and a synchronization information frame transmission section for, in a case where the network terminal acts as a new master terminal of the network system, periodically outputting a synchronization information frame, from the synchronization information frame transmission start time in accord

Abstract: A system for locating a client in a wireless network. The system includes at least three access points. Each access point is adapted to wirelessly communicate with a client having a location using packeted data, be placed in wired data communication within a selected data network; and to share a common precise time reference using the selected data network. The system further includes a switch adapted to translate the relative position of the access points based on a shared common precise time reference and to calculate the location of the client based on a transmission from the client.

Abstract: An apparatus for receiving digital data includes a memory unit for temporarily storing therein a plurality of data streams, each of which includes data and clock obtained by demodulating plural redundant signals received in each receiver in response to a signal generated based on each clock; a writing control unit for controlling a writing of the plurality of the data streams into the memory unit; a data reading control unit for reading the data streams stored temporarily in the memory unit in a synchronized manner; and a selection unit for selecting one of the read data streams to output the selected data stream. The writing control unit detects a synchronization packet included in the plurality of data streams to control the writing of the plurality of data streams into the memory unit based on the synchronization packet.

Abstract: The invention relates to a system and method for coordinating multiple session multimodal interaction. The system and method includes a capability discovery module adapted to discover multimodal capability between at least one client and a multimodal device. The system and method includes an association module adapted to associate multiple independent sessions. The system and method includes a synchronization module adapted to synchronize at least one session with other sessions. And the system and method integrate the at least one client with other devices.

Abstract: A video apparatus having a personal video recorder (PVR) function and a control method thereof are provided. The video apparatus includes a counter which assigns a timestamp to a transport stream packet, a synchronization unit which extracts time information from the transport stream packet, compares the extracted time information with system time information of the video apparatus, and outputs synchronization control information, and a controller which stores an information table created using the timestamp and synchronization control information.

Abstract: The present invention provides methods and systems for detecting a start symbol of a second zone of a frame. One or more symbol indices corresponding to one or more symbols of the second zone of a frame are derived. One or more codes on pilot sub-carriers corresponding to the one or more symbol indices may also be derived. Based on the one or more symbol indices a set of possible start symbol indices is established. Thereafter, a frame is received comprising one or more of a preamble symbol, a first zone and the second zone. It is determined if the received frame comprises the second zone. If the second zone is present in the received frame, the start symbol index of the second zone of the received frame is determined based on the detection of one or more codes and the set of possible start symbol indices. The present invention further provides methods and systems for detecting a Nth symbol of a frame.

Abstract: When data bursts are transmitted between a base station and a mobile receiver, a changeover is made between a plurality of modulation methods during an existing radio link for modulation of the data. For resynchronization of the receiver in the event of the changeover, synchronization information items are determined from a first part (ET) of the data burst modulated by a first modulation method, and are used for synchronization with a second part (ZT) of the data burst modulated by the second modulation method.

Abstract: A system receives multiple data samples and determines time stamp values associated with each of the multiple data samples. The system identifies an earliest time stamp value and uses that time stamp value as an initial system clock value. The system may also subtract a delay factor from the earliest time stamp value to account for delay in decoding the multiple data samples. The earliest time stamp value is also communicated to an audio decoder and a video decoder. The audio and video decoders provide clock data back to a component that maintains the system clock value. If the difference between the clock data received from the decoders and the system clock value exceeds a threshold value, the system clock value is recalculated.

Abstract: Packets used for distributing timing information over a Resilient Packet Ring (RPR) are generated by encoding Synchronization Status Messaging (SSM) messages into IEEE 802.3ah OAM packets (or any other OAM packets, such as those defined in ITU Y.1731). Information indicating the direction that each message is to be transmitted around the RPR ring is also encoded in the packets in either the spare bits of the SSM messages or in the Type-Length-Value (TLV) bytes of the IEEE 802.3ah OAM packets or Y.1731 OAM packets. RPR protection is disabled for the packets carrying the SSM messages and the packets are transmitted to adjacent network nodes in the directions specified by the information encoded in the messages. Information encoded in received packets specifying timing quality and direction of the received messages is observed and compared to determine which timing information included in the messages to use for clock timing.

Abstract: This invention adds one extra bit which can be viewed as a shadow of most significant bit of the serial register. This extra register bit is referred as buffer_flop. When the receive data is coming in, the data bits keep shifting into the serial register of the serializer block bit by bit. The first bits enters into the most significant bit of the serial register and is shifted towards the least significant bit of the serial register. When a whole block of bits (32 bits) are received, the serializer is full and is read into the VBUS clock domain. The first bit of next block of bits is stored in the buffer flop. The second bit is stored in the most significant bit of the serializer and the buffer flop bit is copied into the second most significant bit of the serializer. Subsequent bits are received and right shifted by one.

Abstract: A technique for encoding digital communication signals. Data symbols are augmented in pilot symbols inserted at predetermined positions. The pilot augmented sequence is then fed to a deterministic error correction block encoder, such as a turbo product coder, to output a coded sequence. The symbols in the error correction encoded sequence are then rearranged to ensure that the output symbols derived from input pilot symbols are located at regular, predetermined positions. As a result, channel encoding schemes can more easily be used which benefits from power of two length block sizes.

Abstract: A receiver comprising a processor having an input to receive a sequence of transmission frames conforming to a transmission protocol to represent payload data, a memory arranged to store and to provide to the processor a transmission protocol, a code provider arranged to provide to the processor one or more predetermined codes for association in a predetermined distributed manner within a group of transmission frames of a transmission sequence to represent one or more particular positions in the group of transmission frames, and wherein the processor is arranged to compile at least a portion of one or more distributed codes from a group of transmission frames of a transmission sequence received at the input using the predetermined distributed manner of the one or more predetermined codes received from the code provider, and to compare one or more compiled portions of one or more codes with the one or more predetermined codes received from the code provider to determine one or more particular positions in t

Abstract: The method has two possible transmission modes: a first mode whereby a first transmitter (1) sends frames including sufficient auxiliary data to enable a first receiver (2) to acquire frame synchronization in a reliable fashion, said auxiliary data including a synchronization pattern, a second mode in which said first transmitter sends frames including insufficient auxiliary data to enable said first receiver to acquire said frame synchronization in a reliable fashion but, by virtue of a knowledge of said frame synchronization acquired previously, in said first mode, enabling loss of frame synchronization to be determined, loss of frame synchronization by said first receiver being signalled to said first transmitter by a second transmitter (15) changing from said second transmission mode to said first transmission mode and by a second receiver (16) detecting said change of transmission mode, and said second transmitter transmitting in said second mode modified frames including no payload data sequence imitati

Abstract: 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.