Abstract: According to the method, the focusing servo is activated at the zero-crossing point of a focusing error signal FE immediately after the focusing error signal FE has exceeded the first threshold th1 or has dropped below the second threshold th2. The absolute value of the first threshold th1 and the second threshold th2 is reduced each time a predetermined time t is elapsed until the focusing servo is activated.

Abstract: An information recording/reproducing apparatus includes an optical device, a photo-detector and a calculation unit. The optical device irradiates light beams, including one main beam and at least two sub-beams with respect to an information recording medium. The photo-detector receives return lights of the main beam and sub-beams to output light detection signals. The calculation unit produces a tracking error signal and a position information signal based on the light detection signals. The optical device irradiates the at least two sub-beams onto positions shifted to opposite sides of a center of the guide track, respectively, when the main beam is being irradiated onto a center of the information recording track. Thus, the apparatus produces the tracking error signal and the position information signal by utilizing a common optical system and a common signal processing system and thereby executes tracking servo control and random access processing with high accuracy.

Abstract: An optical disk device for recording data in an optical disk under ZCLV control is provided. The optical disk device divides the optical disk into a plurality of zones, and drives said optical disk at a linear velocity fixed in each zone but varied among the zones. At least one of the linear velocity and the number of zones of the optical disk is controlled in accordance with the amount of data to be recorded. Data recording time is reduced by dynamically changing at least one of the linear velocity and the number of zones of the optical disk in accordance with the amount of data to be recorded, rather than fixing the number of zones and the linear velocity thereof.

Abstract: An optical disk provided with a land region and a groove region that are formed on a substrate, the land region and groove region being used as a recording track that is the medium of the recording/playback of information signal, and a pre-pit region that is formed at the boundary part of neighboring land region and groove region and is disposed every other boundary part, the pre-pit region including specific information. Characteristically, the specific information's in neighboring pre-pit regions are not aligned in the radius direction of the optical disk.

Abstract: A method for synchronizing newly recorded data with previously recorded data. The method is implemented within a disk-based data storage system. A first difference between a wobble reference signal and previously recorded data is measured. Test data is written on a test track to measure a second difference between the wobble reference signal and the test data. The test data is written synchronously with a write clock. An offset value is determined by comparing the first difference and the second difference. New data is then written using the write clock and the offset value such that the new data is synchronized with the old data. To determine the offset value, the test data can be written to the test track with a write clock calibration delay set to zero, the test data can then be read from the test track and the first difference can be subtracted from the second difference to determine the offset value for the write clock calibration delay.

Abstract: An optical drive that detects a communication link interface speed to a host device and changes an optical media writing speed to reduce the likelihood that an error will occur during writing caused by an insufficient data interface rate in relation to the writing speed. In certain embodiments, the process for detecting and storing the preferred recording speed may be a software module which is part of the firmware of the optical drive. The invention provides a method of determining the preferred recording speed based on the interface speed and the maximum recording speed of the optical drive and storing this preferred recording speed for retrieval during recording of optical media.

Abstract: A method of elimination of interference created on CDR/W run-out motors on sledge servers, especially for the elimination of interference created by the run-out of the combination of CDR/W spindle motor on track-seeing servers, where a general evaluating device is provided linking the controller output of the data access module driven by the sledge server motor and the final track signal output, including a speed evaluating device and a run-out evaluating device that may have access to the run-out factor of the CDR/W motor and the CD in the data access module for evaluation of the elimination function of the speed and the run-out tolerance, so that the run-out evaluating device could emit run-out compensation signals for amplification by a relay amplifier and the spindle motor synchronized signal before a negative feedback calculation by playing the final output signal of the module, with access to a play control signal for the elimination of run-out to the CDR/W sledge server, so that the CD may be read, wri

Abstract: A defect detection device for detecting a defect of data recorded on a recording medium includes a waveform state detection part generating information representing a state of a waveform of a reproduced signal from the recording medium based on soft decision results obtained in process of reproducing the data in accordance with a maximum likelihood decoding algorithm corresponding to partial response, and a defect determination part determining the defect of the recorded data based on the information generated in said waveform state detection part.

Abstract: An information storage medium has a logical space managed by a first file system, and the logical space has a space for storing a file used to designate a space area of a second file system, which is different from the first file system.

Abstract: In an information recording medium including a plurality of sector fields and having various pieces of information recorded in the sector fields, the header field in each sector field includes a first field in which a continuously repeated pattern complying with the run length limitation in the predetermined range is recorded, a second field in which an address mark including a violation pattern different from a reproduced pattern obtained by reproducing the repeated pattern when a defective pit which cannot be recognized as a pit is included in pits representing the repeated pattern is recorded, the violation pattern exceeding the run length limitation in the predetermined range, and a third field in which address data is recorded.

Abstract: An electronic device is arranged to be of a thinner structure and to provide a sufficient space required therein. The electronic device has a drive for driving a recording medium in the upper part thereof and incorporates a tray mechanism or a slot-in mechanism for inserting and removing the recording medium from the upper side of the drive.

Abstract: The present invention relates to an apparatus for simultaneously reading from or writing to different information carrier layers of an optical recording medium having at least two different information carrier layers, the apparatus having partial beam generating means for generating different partial beams, focusing means for focusing the partial beams onto different information carrier layers and detection means for detecting the partial beams.

Abstract: An optical head (1) for scanning optical record carriers (2) is provided with a compensator (16) for compensating spherical aberration of the objective system (18) or defocus of the collimator lens (14) caused by operation of the optical head at a temperature different from the design temperature. A surface of the compensator (16) comprises a phase structure in the form of annular areas (52, 53, 54), the areas forming a non-periodic pattern of optical paths of different length. The optical paths change as a function of temperature and form a temperature-dependent wavefront deviation that compensates the spherical aberration and/or defocus.

Abstract: A magnet used for an actuator of an optical pickup has a magnetization pattern has two different pole areas adjacent with each other. At a corner part defined by the boundary line of the two pole areas, the pole area inside the corner part has a projection area, projecting in the direction of the pole area outside the corner part. Owing to the existence of the projection area, insufficiency of the magnetic flux density at the corner part particularly close to the vertex can be improved so that a desirable magnetic field can be provided to the printed coil substrate disposed in the vicinity of the magnet.

Abstract: A disk recording and/or reproducing apparatus is provided with:

Abstract: There is a problem that a high fitting accuracy between the table body and a chucking ring of a turntable is requested because the table body and the chucking ring are separately constituted and the chucking ring is integrated with the table body by fitting the ring to the body. The present invention relates to a disk drive comprising a turntable (47) on which an optical disk (33) used to reproduce an information signal is mounted and a spindle motor (51) to whose rotating portion the turntable (47) is set. The turntable (47) is provided with a mounting portion (47a) on which the optical disk (33) is mounted and a fitting portion (47b) to be fitted to the center hole (33a) of the optical disk (33) and having an elastic piece (14b) to be pressure-welded to the inner periphery of the center hole (33a), in which the mounting portion (47a) and the fitting portion (47b) are formed into one body.

Abstract: A DVD-Audio which includes a data zone for storing data to be reproduced and an information zone for storing information on the data to be reproduced. The information zone includes directories of a video title set (VIDEO_TS) and an audio title set (AUDIO_TS). The AUDIO_TS directory includes information on an audio manager (AMG) having information on audio titles. The data zone includes the audio titles each having an audio title set information (ATSI) followed by a plurality of contiguous audio objects (AOBs). The ATSI includes a plurality of audio stream attributes each having an audio coding mode, first to third quantization bit numbers, first to third sampling frequencies and decoding algorithm information relating to the number of audio channels. Each of the AOBs includes a plurality of audio packs recorded with audio data corresponding to the decoding algorithm stored in the audio stream attribute.

Abstract: A rewritable optical information recording medium includes a transparent substrate on which a groove is formed, and a recording layer on which frequency-modulated address information is recorded by wobbling the groove. The recording layer is provided on the transparent substrate. In the rewritable optical information recording medium, J(M)/M≦0.17 is satisfied where J(M) is relative jitter with respect to a basic clock T0 and M is a degree of modulation of recorded signal. The relative jitter J(M) is given by J(M)=T&sgr;(M)/T0 when T&sgr;(M) is jitter with respect to the degree of modulation M. The jitter T&sgr;(M) is caused in the demodulated address information which is one modulated according to mark length modulation.

Abstract: A code-enhanced, multi-user detection, Reduced Algorithm Receiver in a multiuser communication system reduces the signal processing requirements by limiting the number of searches between consecutive symbol cycles using information from an encoder state diagram. The Receiver makes use of a convolutional encoder's state machine properties to mark possible transitions as invalid based on the current state of the multiple users'encoders, thus removing them from the search tree.

Abstract: A method of transmission level security, and a corresponding transmission security system, the method consists of the steps of: forming a plurality of digital signals representing a symbol to be transmitted over a communication medium, wherein respective ones of the plurality of digital signals are modulated onto respective ones of a plurality of subcarriers according to a multiple carrier modulation scheme; and introducing a predetermined group delay distortion in one or more of the plurality of subcarriers, such that portions of the one or more of the plurality of subcarriers will be received outside of a time window corresponding to the symbol at a receiver. In one implementation, an equipped receiver substantially removes the predetermined group delay distortion such that the portions of the one or more of the plurality of subcarrier fit within the time window.

Abstract: Medium access control device (301) for a mobile network station (3, 4, 5) or an access point (AP1) in a wireless local area network (1), having controlling means (302), processing means (303) and transmitting and receiving means (304); the controlling means (302) being arranged to control transmission and reception of radio frequency data signals containing data symbols; the transmitting and receiving means (304) being arranged for transmission and reception of electromagnetic data signals; the processing means (303) being arranged for detecting a first signal portion and a second signal portion in the received data signal, the second signal portion following the first signal portion and having a signal coding differing from a signal coding of the first signal portion.

Abstract: Optical code-division multiplexing and demultiplexing (CDM) using orthogonal codes with minimum shift keying (MSK) waveforms allows more efficient use of the spectrum and greatly reduces cross-channel interference. Receiving multiple baseband data channels, a derivation mechanism converts the data signals into series of impulses. These impulses may be split into odd and even channels, each at half the original data rate, and transmitted to a plurality of Walsh filters configured to have an impulse response corresponding to one of a plurality of orthogonal MSK waveforms. Odd and even channels, encoded with MSK waveforms, may combine into an in-phase and quadrature channel, 90° out of phase. A laser output may be divided, phase shifted, and modulated with the in-phase and quadrature channels, which divisions are then combined into a single multiplexed output. Walsh filters may decode the incoming signal in order to reproduce the original baseband channels.

Abstract: Two multi-rate transmission schemes, multi-code (MC) and variable-spreading-length (VSL) code, for realizing multimedia communications on three types of OFDM-CDMA systems are proposed. These systems can be integrated into a programmable structure such that the operation can be controlled and adjusted by system parameters and thus the transceiver can be used in different systems without changing the fundamental hardware and software architecture, which serves the trend of software-radio for future application. A transceiver architecture of multi-rate OFDM-CDMA systems is illustrated and showed its programmability such that the general system can operate under different scenarios with a common hardware structure and reconfigure by software implementation.

Abstract: A system for a sliding-window transform with integrated windowing is described. The system provides a Direct Fourier Transform kernel with an integrated windowing filter having a desired number of stages. In one embodiment, the windowing filter is a lowpass filter. In one embodiment, the lowpass filter has a rectangular filter transfer characteristic. The DFT includes a complex multiplier. A first portion of the windowing filter is provided before the complex multiplier and can be implemented using real arithmetic. A second portion of the windowing filter is provided after the complex multiplier and is implemented using complex arithmetic. In one embodiment, the filter weights of the second portion of the windowing filter are unity and thus no multiplier is needed for the filter weights in the second portion of the windowing filter.

Abstract: Redundancy is established over a radio link (RL) between peripheral units (28) of a communications network (20). The communications network includes a central unit (26) which is connected by a first link (LA) to a first peripheral unit (28A) and by a second link (LB) to a second peripheral unit (28B). The radio link connects the first peripheral unit and the second peripheral unit. Redundancy is realized by providing communication between the central unit and the second peripheral unit over the radio link upon failure of the second link. In one illustrated example implementation, the communications network is a radio access network of a telecommunications system, with the central unit being a radio network control (RNC) node and the first peripheral unit and the second peripheral unit being differing base stations of the radio access network.

Abstract: Described is a method of managing multiple failures of different type in telecommunication networks having a ring topology, in particular transoceanic four-fiber MS-SPRING rings. The method is characterized by comprising the step, implemented before realizing the ring type protection, of checking that the necessary low priority channels for the implementation of the ring type protection are available, namely they are not already utilized for performing another protection; in the negative case, it is foreseen the implementation of no ring type protection to prevent the unuseful loss of low priority channels. In case of multiple failures of different type, namely of ring and span types, in the path, the method provides for implementing a ring type protection.

Abstract: The blocks to be sent on one or more physical channels for packet mode transmission pertain to several temporary block flows to terminals. The terminals are distributed into several subscription classes corresponding to various priority levels and each associated with a throughput restriction parameter. Transmission throughputs allocated to the flows as a function of transmission throughputs respectively requested during the creation of the flows and restriction parameters associated with the subscription classes are determined. At least one traffic channel supported by a physical channel is allotted to each new flow created. For each send period on a physical channel, a flow to which a traffic channel supported by this physical channel is allotted, is selected with the aid of the values of the transmission throughputs allocated, so as to send a block of the selected flow in the course of said period.

Abstract: A system and method for input thresholding packets in a network switch. A network switch may include multiple input ports, multiple output ports, and a shared random access memory coupled to the input ports and output ports by data transport logic. Packets entering the network switch may be assigned to one of a plurality of threshold groups and to one of a plurality of flows within the threshold group. In one embodiment, each threshold group may be divided into a plurality of levels of operation. As resources are allocated or freed by the threshold group, the threshold group may dynamically move up or down in the levels of operation. Within each level, one or more different values may be used as level boundaries and resource limits for flows within the threshold group. In one embodiment, programmable registers may be used to store these values.

Abstract: A system and method for late-dropping packets in a network switch. A network switch may include multiple input ports, multiple output ports, and a shared random access memory coupled to the input ports and output ports by data transport logic. Packets entering the switch may be subject to input thresholding, and may be assigned to a flow within a group. A portion of a packet subject to input thresholding may be accepted into the switch and assigned to a group and flow even if, at the time of arrival of the portion, there are not enough resources available to receive the remainder of the packet. This partial receipt of the packet is allowed because of the possibility of additional resources becoming available between the time of receipt of and resource allocation for the portion of the packet and receipt of subsequent portions of the packet.

Abstract: Disclosed is a method and system for controlling congestion control in a packet data communication network in which a plurality of data is transmitted from a source node to a destination node. Depending on the congestion state in the network, the sender rate at which the source node is transmitting the data is adjusted based on the congestion feedback information and the bandwidth capacity of the network. The adjustment of the sender rate is performed according to predetermined criteria to establish a maximum data transmission rate and maximum fairness for the source.

Abstract: A telecommunications network includes a plurality of user nodes, a relay node, and controller means. The controller means is operative to allocate resources so as to control levels of traffic transmitted form/to the user nodes via the relay node. Specifically, the controller means is operative to allocate a data transmission rate for traffic from user nodes via the relay node to user nodes which is twice that for traffic via the relay node in from or out of the network.

Abstract: A method for eliminating loops in a communication network in which the nodes operate as virtual bridges, having virtual ports that link the virtual bridges over virtual connections, each of the virtual connections coinciding respectively with one or more segments of the network. Respective port costs are assigned to the virtual ports responsive to a count of the network segments with which the respective virtual connections coincide, so as to favor virtual paths between pairs of the nodes that are made up of a greater number of the virtual connections, relative to the virtual paths that are made up of a lesser number of the virtual connections. Respective path costs are computed for the virtual paths, based on the port costs, and the virtual connections over which to send traffic between the virtual bridges are selected responsive to the path costs.

Abstract: A hierarchized path setting system in a communication network efficiently contains lower order paths in higher order path. The communication network has a plurality of nodes capable to perform switching process and demultiplexing process not only for lower order paths in a predetermined hierarchical level among hierarchized paths but also for higher order paths in a hierarchical level higher than the predetermined hierarchical level, and a plurality of links connecting these nodes. The system is responsive to a new path setting demand for setting the lower order path, for setting the lower order path in the higher order path when a single higher order path is set from a predetermined transmiter node group, in which a transmiter node of the lower order path belongs, to a predetermined receiver node group including a receiver node.

Abstract: A method for sending a data packet (DP), which directly or indirectly indicates a quality-of-service requirement (QoS), to a mobile node (MN) from a correspondent node (MCN) via a multi-bearer network, or MBN, which provides at least one interface unit (IU) to each of multiple alternative bearer networks (BN) between the MBN and the mobile node. The method comprises selecting an optimal bearer network (BN) for sending a data packet (DP) between the MBN and the mobile node (MN) based on 1) the quality-of-service requirement (QoS) of the data packet (DP) in question; 2) traffic load data (41) related to the multiple bearers; 3) interface unit availability information (PIU, 42); and 4) bearer type preference information (PBT, 43).

Abstract: A method and system are described herein for obtaining IGP network information useful in determining network routing topologies. The method involves querying a router for its router identifier and all its area identifiers, counting the router's number of area identifiers to determine whether the router is an ABR or an ASBR, and querying the router's link state database for the lowest area identifier on the router. The method further involves importing all Type 1 and Type 2 LSAs for that area into the database of a network discovery software engine, importing from the router's link state database only those networks outside the router's autonomous system that are also directly connected to an ASBR, then moving to the next highest area identifier in the router's database to repeat importing Type 1 and Type 2 LSAs for that area into the database.

Abstract: An ad hoc network is formed as a connection between a local area network with its services and at least one body-worn network when at least one computer in the local area network detects the local services located in the local area network, translates them into Jini services and offers them on the IP plane with the use of Jini middleware for body-worn networks.

Abstract: A method for distributing participants of a conference handled by a first conference unit in a packet switched network is disclosed. This is provided by, when a first condition is reached, locating a second conference unit satisfying a second condition, reserving conference call capacity in said second conference unit, transferring one or more of said participants from the first to the second conference unit and preferably entering said first conference unit as a participant in said second conference unit, wherein data streams of possible conference participants still attached to the first conference unit are mixed in the first conference unit and communicated as one data stream to the second conference unit.

Abstract: Disclosed is a system and method for optimizing capacity in a multi-user time division duplex (“TDD”) communication system such as a broadband wireless radio frequency communication system. More specifically the invention minimizes guard time in duplexed signals to thereby allow for higher data throughput which results in an increase in system communication capacity. Depending upon instantaneous traffic load associated with the subscribers using a particular TDD carrier, guard times may be adjusted to provide a desired level of throughput. As traffic loads demand, the order of assignment of burst periods in either or both the transmit and receive frames of a TDD carrier with respect to the subscriber systems operable thereon are adjusted to accommodate desired guard times.

Abstract: A method of implementing a repeater in a data transmission system, and a transceiver unit for a data transmission system, whereby the transceiver unit (9) comprises a first (71) and a second (72) transceiver block which can function parallel on different frequency bands with the same part of the data transmission connection, means (91) for allowing the series connection of said transceiver blocks (71 and 72), and means (tx1, rx1, tx2, rx2) for connecting the transceiver unit to the data transmission connection such that the receiver input and transmitter output of the first transceiver block (71) are connected to the first part (3A) of the data transmission connection and the receiver input and transmitter output of the second transceiver block (72) are connected to the second part (3B) of the data transmission connection.

Abstract: A circuit apparatus of extending General Purpose Input Output pins, which includes a control processing unit, a memory, and a buffer. Wherein, data pins of the control processing unit is coupled to memory pins of the memory and those in the buffer. Input signals can be temporarily stored in the buffer when the buffer is used as a buffer for inputting signals. And the buffer can feed input signals into the control processing unit while the memory is being recharged. Likewise, if the buffer is used as a buffer for outputting signals, the buffer can receive output signals (So) from the control processing unit and output those signals while the memory is being refreshed.

Abstract: To avoid lost packets that could otherwise occur were a round robin scheduling policy to be used to assign PPP packet fragments to multiple communication links, the links are assigned tokens based on their capacities, with a fragment being assigned to the link with the most tokens. When a fragment is scheduled to a link, the tokens of the link are decremented accordingly. The tokens are periodically refreshed.

Abstract: A common power control channel transmission device for a base station in a CDMA communication system is provided having a selector for receiving power control commands to be transmitted to multiple subscribers and multiplexing the received power control commands; and a spreading modulator for spreading an output of the selector by multiplying the output of the selector by a spreading sequence. The common power control channel transmission device can be used to control power of a reverse link common channel. For the power control of the reverse link common channel, the base station receives a signal from a mobile station via the reverse link common channel, and transmits to the mobile station a power control command for controlling a transmission power of the reverse link common channel according to a measured strength of the received signal.

Abstract: A system and related methods to facilitate the delivery of enhanced data services in a mobile wireless communications environment is generally described. According to one aspect of the invention, a data networking protocol is introduced generally comprising control commands and attribute-value pairs. The one or more control commands including one or more control commands selectively employed to establish, manage and tear-down a communication session by and between elements of a data network. The one or more attribute-value pair(s) (AVP), selectively employed by a network element to define one or more parameters of an accompanying control command, the AVPs including one or more mobility management AVPs to facilitate exchange of mobility information between at least a subset of the network elements of the data network participating in a point-to-point component of the communication session.

Abstract: A method and apparatus splits information into subsets of information to be communicated for a wireless apparatus. The split information (512a-512d) is transmitted to a plurality of proximal wireless units (106b-106n). The plurality of proximal wireless units convey at least some of the transmitted split information to a destination wireless apparatus (106a). This splitting operation is used in both uplink and downlink communications.

Abstract: A group of independent wireless apparatus (106a-106n) in a wireless local area network are identified and coordinated (aggregated) using the short-range wireless area network (wireless LAN). Each wireless apparatus receives information from a wireless wide area network (wireless WAN) such as a conventional cellular system. The plurality of independent proximal wireless apparatus (106b-106n) receive the same information that is ultimately destined for one of the wireless apparatus in the proximal group in the wireless local area network. Each proximal wireless apparatus (106b-106n) that has received the same information from the wide area network then retransmits or forwards the same information to the destination wireless apparatus (106a). Accordingly, the plurality of wireless apparatus in the local area network receive the same information from a wide area network and forward it, using the short range wireless communication system, to a destination wireless apparatus in the local area network.

Abstract: The present invention employs training sequence hopping in a cellular communications system to permit tight frequency reuse by minimizing or avoiding co-channel interference and/or other signal degrading phenomena. During a first portion of a transmission, e.g., a first burst, a first training sequence is used. During a second portion of that transmission, e.g., a second burst, a second different training sequence is used. Different training sequences are used for different portions of the transmission according to a predetermined training sequence hopping pattern and with a predetermined number of training sequences. The portion during can extend for the length of a burst, for more than one burst, for a speech frame, or for some other time period.

Abstract: An encoding method in a mobile communication system, for receiving 4 input information bits, encoding the 4 input information bits with different Walsh codes of length 16, and outputting a coded symbol stream having 24 coded symbols using a coded symbol stream having 16 coded symbols obtained by XORing the encoded input information bits by an XOR operator. The encoding method comprises repeating the coded symbol stream having 16 coded symbols once, and thus outputting a coded symbol stream having 32 coded symbols; and puncturing 0th, 1st, 2nd, 3rd, 4th, 5th, 6th and 16th symbols from the 32 coded symbols, and thus outputting the coded symbol stream having 24 coded symbols.

Abstract: A mobile communications terminal has a transmitter for transmitting a specific identification code of a reference base station as a time reference for network position determination. Therefore, a position server connected with a CDMA network can distinguish the reference base station from the other base stations regardless of positioning relationship between the mobile terminal and the base stations.

Abstract: A public communication system and method is disclosed which can provide a necessary high speed service flexibly when necessary. A W-CDMA system is used to integrate a plurality of communication networks having different service objects from one another such as a medical (fire service) network, a police network, undertaker networks and a general public network to construct a single common communication system. User terminals such as medical (fire service) high function mobile communication terminals, police high function mobile communication terminals, undertaker high function mobile communication terminals and portable telephone terminals are connected to the W-CDMA system through the air interface. The common communication system controls so that baseband resources are allocated to the user terminals based on priority levels of the user terminals.

Abstract: A physical channel of a user service is provided for assignment to a set of time slots in a hybrid time division multiple access/code division multiple access wireless communication system. A measure of interference is determined for each of the set of time slots. A fragmentation parameter is provided. The fragmentation parameter represents a preference for fragmenting user service physical channels over time slots. The user service physical channel is assigned to one of the set of time slots using the measured interference associated with each of the set of time slots and the fragmentation parameter.