Showing papers on "Data transmission published in 2000"

Peak-to-average power ratio reduction of an OFDM signal using partial transmit sequences

Abstract: Orthogonal frequency-division multiplexing (OFDM) is an attractive technique for achieving high-bit-rate wireless data transmission. However, the potentially large peak-to-average power ratio (PAP) has limited its application. Recently, two promising techniques for improving the PAP statistics of an OFDM signal have been proposed: the selective mapping and partial transmit sequence approaches. Here, we present suboptimal strategies for combining partial transmit sequences that achieve similar performance but with reduced complexity.

Data transfer and synchronization system

Abstract: A data transmission system is disclosed which optimizes transfer and updates of information between systems by providing difference information between the systems. The system transmits data packages having instructions for manipulating user data. The data packages include a header identifying the respective packages, as well as transaction objects for effecting a change to user data on a device having object instructions.

Securing information by use of digital holography.

Abstract: An information security method that uses a digital holographic technique is presented. An encrypted image is stored as a digital hologram. The decryption key is also stored as a digital hologram. The encrypted image can be electrically decrypted by use of the digital hologram of the key. This security technique provides secure storage and data transmission. Experimental results are presented to demonstrate the proposed method.

Software, systems and methods for managing a distributed network

Abstract: Software, system and methods for managing a distributed network (10) environment including a plurality of computers (22,24) interconnected by a network link (24), where at least some of the computers include a layered communication protocol stack (92) for providing a data interface between an application program (98, 122) and the network link, the communications stack having a transport protocol layer (124) for providing an end-to-end communications connection The invention includes a control module (132) and a plurality of agents (70), each agent being associated with one of the computers and adapted to dynamically monitor the associated computer at a data transmission point between an application program running on the computer and the transport protocol layer and repeatedly communicate with the control module (132) in order to effect management of the distributed network system The invented software, system and methods may also include a messaging feature for providing users, IT personnel, or various management systems with informative messages concerning network conditions and network resources

System and method for transporting a compressed video and data bit stream over a communication channel

Abstract: Digitally compressed video/audio bit streams, when transmitted over digital communication channels such as digital subscriber loop (DSL) access networks, ATM networks, satellite, or wireless digital transmission facilities, can be corrupted due to lack of sufficient channel bandwidth. This invention describes schemes to ensure lossless transmission of bit streams containing pre-compressed video signals within the communication channels. The schemes herein comprises a rate conversion system that converts the bit rate of a pre-compressed video bit stream from one bit rate to another, and that is integrated with a digital communication channel, and a means to convey the maximum channel transmission rate to the rate conversion system to allow satisfactory transmission of the bit stream from the input of the rate converter through the transmission facility.

PSockets: The Case for Application-level Network Striping for Data Intensive Applications using High Speed Wide Area Networks

Abstract: Transmission Control Protocol (TCP) is used by various applications to achieve reliable data transfer. TCP was originally designed for unreliable networks. With the emergence of high-speed wide area networks various improvements have been applied to TCP to reduce latency and achieve improved bandwidth. The improvement is achieved by having system administrators tune the network and can take a considerable amount of time. This paper introduces PSockets (Parallel Sockets), a library that achieves an equivalent performance without manual tuning. The basic idea behind PSockets is to exploit network striping. By network striping we mean striping partitioned data across several open sockets. We describe experimental studies using PSockets over the Abilene network. We show in particular that network striping using PSockets is effective for high performance data intensive computing applications using geographically distributed data.

Study on intelligent battery charging using inductive transmission of power and information

Abstract: In previous literature, the authors introduced the technology of the wireless transmission of power and information (WTPI). This paper introduces an effective application of WTPI technology to the safe and optimal power supply for battery charging systems. In this paper, the effectiveness of the proposed closed-loop charging through the WTPI coupling is highlighted. For the practical application of the proposed charging, the power transmission efficiency of the WTPI must be high, and data transmission by way of the WTPI coupling needs to be bidirectional and fast enough for the real-time data feedback and charging control. By analyzes on the transmission performance using equivalent circuits, the power transmission efficiency of about 92% and the data transmission bandwidth of 8.5 Mbps are obtained with the practical WTPI coupling configuration. The charging condition is optimized, according to the proposed estimation of the residual battery capacity. As a result, the time for completion of charging is minimized by 30% and the life of the battery is elongated by 20%.

On-demand overlay routing for computer-based communication networks

Abstract: Methods and apparatus are disclosed for dynamically discovering and utilizing an optimized network path through overlay routing for the transmission of data. A determination whether to use a default network path or to instead use an alternate data forwarding path through one or more overlay nodes is based on real-time measurement of costs associated with the alternative paths, in response to a user request for transmission of message data to a destination on the network. Cost metrics include delay, throughput, jitter, loss, and security. The system chooses the best path among the default forwarding path and the multiple alternate forwarding paths, and implements appropriate control actions to force data transmission along the chosen path. No modification of established network communication protocols is required.

Apparatus and method for implementing digital communications on a power line

Abstract: An apparatus to establish bi-directional digital communication over a power line network includes a signal launching circuit (305T) to impose a digital communication signal onto a power signal carried by a power line network. The signal launching circuit is configured to position a pulse of the digital communication signal at any phase location of each half cycle of the power signal. A receiver (306) leads the digital communication power signal at a second point in the power line network. A signal processor (604) is connected to the receiver to recover the digital communication signal from the digital communication power signal.

System and method for requesting and dispensing negotiable instruments

Abstract: The present invention provides a system and method for requesting and dispensing negotiable instruments such as bank checks, money orders, and traveler's checks. An instrument may be requested in this system and method by a bank customer from a telephone, a computer, a fixed-location dispenser, or a portable, hand-held dispenser that is in communication with a bank computer. This request may be made orally, using touch tones, or using data transmission over a communication network that may include telephone lines, two-way radio links, microwave links, satellite links, cellular telephone links, computer networks, and the Internet. After a request is processed and approved, the requested instrument may then be dispensed at any time in this system and method to the bank customer or another party from any receive-only dispenser, fixed-location dispenser, or portable, hand-held dispenser that is also in communication with the bank computer.

A flexible system and method for communicating between a broad range of networks and devices

Abstract: A flexible gateway accommodates data transfer from a data origination device over a wide variety of networks to a wide variety of destination devices, even if those networks use different protocols, and even if the devices recognize different data formats. Thus, the gateway can perform work previously requiring numerous gateways. After the gateway receives information from a data source, the gateway identifies the specific device type and the specific network type to which the information is to be routed. The gateway then calls device and network drivers associated with the specific device and network identified with the destination device. These drivers then manipulate the data using the device driver into the format recognized by the destination device, and then provide the manipulated data to the destination device over the identified network using the compatible protocol. Thus, the destination device properly receives and interprets the information provided by the data source. If, in the very next moment, data arrives at the gateway that is to be routed over a different network using a different protocol to a different device recognizing a different device, the gateway will call different device and network drivers to enable the communication.

Chaotic pulse position modulation: a robust method of communicating with chaos

Abstract: In this letter we investigate a communication strategy for digital ultra-wide bandwidth impulse radio, where the separation between the adjacent pulses is chaotic arising from a dynamical system with irregular behavior. A pulse position method is used to modulate binary information onto the carrier. The receiver is synchronized to the chaotic pulse train, thus providing the time reference for information extraction. We characterize the performance of this scheme in terms of error probability versus E/sub b//N/sub 0/ by numerically simulating its operation in the presence of noise and filtering.

Implanted medical device telemetry using integrated microelectromechanical filtering

Abstract: A telemetry receiver for an implantable medical device such as a cardiac pacemaker has an RF antenna coupled to a telemetry circuit that includes an out-of-band rejection filter comprising a microelectromechanical filter. The telemetry circuit further includes an amplifier coupled to the microelectromechanical filter and a demodulator coupled to the amplifier. The filter, amplifier and demodulator are all fabricated on a common integrated circuit die. A multichannel telemetry receiver for an implantable medical device has a plurality of microelectromechanical bandpass filters defining individual channels. A multiplexing circuit selects the signal of an individual bandpass filter channel for application to a demodulator circuit that recovers programming data from a modulated RF transmission from a programming unit. Identification of a preferred data transmission channel for communication of programming data to the implanted medical device is determined by obtaining samples of the signals being passed by each of a plurality of microelectromechanical bandpass filters that define individual channels and evaluating the samples to determine the noise level for each channel. The implantable medical device may be programmed to receive downlink telemetry communications from a programming unit on the channel identified as being the preferred data transmission channel having the lowest noise level.

Method and apparatus for dynamic spectrum allocation

Abstract: A transceiver device (52 or 10) operates as a source of a data transmission in a communication system (50) capable of dynamically allocating spectrum for transmission of the data transmission between the transceiver device (52) and a second transceiver device (51). The transceiver device (10) includes a transmitter, a receiver coupled to the transmitter and a processor or controller (12) coupled to the transmitter and receiver. The transceiver device is programmed to monitor the spectrum (channels 1-13 of FIG. 3) to determine if a portion (channels 4-8 for example in time slot 8) of the spectrum is available. The transceiver determines what portion of the spectrum is desired for data transmission and then transmits (see time slots 11 and 13) the data transmission within a dynamically selected portion of the available spectrum.

Forward error correction with channel adaptation

Abstract: A transmit-configuration mechanism (52) for configuring an FEC encoder (34) (including an associated interleaver (84)) for changing data channel characteristics Channel information specifying a modulation mode and carriers capable of supporting the modulation mode for the data channel is received by a transmitting network node (12a) for use in a data transmission to a receiving network node (12b) The received channel information is based on a prior data transmission to the receiving network node (12b) over the data channel Configuration values are computed from the received channel information and an amount of data to be transmitted in a data transmission The FEC encoder (34) is configured to operate on the data transmission data amount according to the configuration information

Communicatory navigation system

Abstract: Disclosed is a communicatory navigation system including an information center ( 150 ), at least one navigation unit ( 100 ) each mounted on a vehicle and communication means for allowing bi-directional data communication between the information center and the navigation unit. Data transmission from the navigation unit to the information center is made during a period of communication that begins when the navigation unit become communicable with the information center and ends when the bi-directional data communication therebetween is disconnected. The navigation unit is provided with a drive route history memory area ( 131 ) and an instrument operation history memory area ( 132 ), and data in these memory areas are transmitted to the information center, together with the vehicle current position data and the destination position data. The information center determines a recommended drive route from the current position to the destination, not only with reference to its own database ( 158 ) but also taking into consideration the history data. For example, if it is determined that there is a traffic accident or heavy traffic jam in some route, a bypass route is determined and transmitted back to the navigation unit. When the previous drive route indicated by data in area ( 131 ) is not found in the database ( 158 ), it can be recognized as a newly constructed road for inclusion in the database.

Performance analysis for voice/data integration on a finite-buffer mobile system

Abstract: Personal communication service (PCS) networks offer mobile users diverse telecommunication applications, such as voice, data, and image, with different bandwidth and quality-of-service (QoS) requirements. This paper proposes an analytical model to investigate the performance of an integrated voice/data mobile network with finite data buffer in terms of voice-call blocking probability, data loss probability, and mean data delay. The model is based on the movable-boundary scheme that dynamically adjusts the number of channels for voice and data traffic. With the movable-boundary scheme, the bandwidth can be utilized efficiently while satisfying the QoS requirements for voice and data traffic. Using our model, the impact of hot-spot traffic in the heterogeneous PCS networks, in which the parameters (e.g., number of channels, voice, and data arrival rates) of cells can be varied, can be effectively analyzed. In addition, an iterative algorithm based on our model is proposed to determine the handoff traffic, which computes the system performance in polynomial-bounded time. The analytical model is validated by simulation.

Multi-parameter capability transmitter for wireless telemetry systems

Abstract: A transmitter 110 physically comprises a (local) sensor 120 , normally located within a transmitter casing 130 , for sensing a first parameter, a data transmission unit 140 for providing a wireless transmission to a receiver 150 of the telemetry system 100 , and a coupling unit 170 for coupling one or more remote sensors 200 i to the transmitter. While the transmitter is designed to transmit signals from the local sensor, it also allows to further or alternatively transmit signals from one or more remote sensors coupled to the coupling unit. This allows changing monitoring from one parameter to another parameter by simply coupling another remote sensor to the coupling unit.

High speed data transfer mechanism

Abstract: A storage and data management system establishes a data transfer pipeline between an application and a storage media using a source data mover and a destination data mover. The data movers are modular software entities which compartmentalize the differences between operating systems and media types. In addition, they independently interact to perform encryption, compression, etc., based on the content of a file as it is being communicated through the pipeline. Headers and chunking of data occurs when beneficial without the application ever having to be aware. Faster access times and storage mapping offer enhanced user interaction.

Method and apparatus for efficient data transmission in a voice-over-data communication system

Abstract: A method and apparatus for increasing the probability of successful data frame transmission from a transmitter to a receiver. When a data frame is generated by a processor (210), it is stored in a transmit queue (212) and a copy of the data frame is stored in a secondary queue (214). An elapsed time device (220) tracks the elapsed time that the data frame copy has been stored in the secondary queue (214). When no data frames are generated by the processor (210), data frame copies from the secondary queue (214) are placed into the transmit queue (212), thereby increasing the redundancy of transmitted data frames and thus the probability of successful transmission to the receiver.

Apparatus and method of maintaining state in a data transmission system

Abstract: An apparatus and method of maintaining state information for a network device changing from a first channel (in communication with a first base unit) to a second channel (in communication with a second base unit) communicates with at least one of the first base unit and an intermediate network device to ascertain the state information. Once the state information is ascertained, it is applied to the communication of the network device with the second base unit. Both the first and second base units are independently operable network devices in a data transmission network.

An efficient bit-loading algorithm for DMT applications

Abstract: This letter describes an efficient bit allocation algorithm for digital subscriber loop modems that use discrete multi-tone technology. The algorithm computes the optimum bit allocation profile within all constraints and requires fewer computations than the conventional "water-filling" approach. Conventional algorithms are unable to assign data bits to higher frequency bins over long loops with high level of interference due to the power spectrum mask limitation, even if the total power budget is not expended. We propose a novel scheme to distribute data over multiple bins at correspondingly reduced power in these, otherwise unpopulated bins.

Millimeter-wave broad-band fiber-wireless system incorporating baseband data transmission over fiber and remote LO delivery

Abstract: We present the first demonstration of a millimeter-wave (mm-wave) broadband fiber-wireless system which incorporates baseband data transmission in both the downstream (622 Mb/s) and upstream (155 Mb/s) directions. The local oscillator (LO) required at the remote antenna base station for up- and downconversion to/from the mm-wave radio frequency (RF) is delivered remotely via a modulation scheme that is tolerant to the effects of fiber chromatic dispersion on the detected LO carrier power. The technique employs a single dual electrode modulator located at the central office (CO) and the data and an RF signal at a frequency equal to half the LO frequency, are applied simultaneously to the device. The modulation scheme was optimized as a function of the modulator operating conditions. Simultaneous bidirectional radio transmission in the mm-wave fiber-wireless network was implemented using specially designed mm-wave diplexers located at the base station (BS) and customer unit, and a single Ka-band printed antenna array at the BS operating simultaneously in transmit and receive mode. Error-free data transmission was demonstrated for both down(34.8 GHz) and uplinks (37.5 GHz) after 20 km of single-mode optical fiber and a bit error rate (BER) of 10/sup -6/ was achieved after the inclusion of a 2-m radio link.

Frequency-offset synchronization and channel estimation for OFDM-based transmission

Abstract: This letter is concerned with a frequency offset estimation technique for OFDM based transmission systems. The frequency estimation technique utilizes a repetitive signal structure inside of a OFDM symbol which is used to enlarge the range and increase the accuracy of offset estimation. Also, an averaged decision-directed channel estimation (ADDCE) technique suitable for burst data is proposed.

Radio network performance of Bluetooth

Abstract: A new radio interface named Bluetooth has been developed to provide short range connectivity between various consumer devices. The Bluetooth system operates in the unlicensed 2.45 GHz ISM band and applies frequency hopping over 79 carriers. This paper presents the simulation results of the radio network performance of a large number of co-located Bluetooth units. For a capacity-demanding WWW data traffic model, the interference caused by (on average) 100 concurrent sessions in a single room of size 10 m/spl times/20 m results only in a 5% degradation of the aggregate throughput. In general, it is advisable to use long uncoded packet types for data transmission since they have the largest ideal throughput and therefore generate the least interference power. For real-time speech links, frame erasures represent the dominant reason for transmission quality degradation, more than residual payload bit errors. It is thus advisable to use the provided uncoded packet type in order to allow for the largest capacity; a system load of about 30 Erlang yields an average frame erasure rate of 1%.

Method and apparatus for improving transmission performance over wavelength division multiplexed optical communication links using forward error correction coding

Abstract: Data transmission apparatus includes optical transmitters (14a, 14b) coupled to an optical link (10). A FEC coder (40) is coupled to the input of transmitter (14b'). A first signal (12a) having a first rate is provided to the first transmitter, and a second signal (12b) having a higher information rate than the first signal, while simultaneously enabling the respective output power levels of the amplifiers (18a, 18b). The transmission apparatus achieves higher transmission capacity while retaining compatibility with pre-existing fiber spans and amplifier nodes. An optical transmission system incorporates a transmitter (70) and a receiver (72) having certain transmission characteristics, such as output power level, decision threshold level, etc., that are adjustable in response to BER. A BER estimator (74) is provided at the receiving end of the link. The estimator estimates the BER of the received signal, and provides BER to the receiver, and/or transmitter, and/or optical link, based on the estimated BER, to optimize performance.

Apparatus, method and system for multimedia access network channel management

Abstract: An apparatus, method and system are provided for multimedia access network channel management, such as channel management in a hybrid fiber-coaxial cable network, for voice (telephony), video, fax and data transmission The preferred system embodiment includes a plurality of cable telephony modems (CTMs), for such voice (telephony), video, fax and data transmission, and includes a cable modem termination system (CMTS) For upstream communication from the CTMs to the CMTS, the network provides a plurality of channels, formed by a combination of FDM and TDMA When a CMTS receives an multimedia network access message having a comparative priority from a CTM, the CMTS determines whether there is a first channel which is available from the plurality of channels, and if so, assigns a first transmission corresponding to the multimedia network access message to the first channel When there is no available first channel, the CMTS determines whether there is a second transmission on a second channel which is moveable to a third channel, and if so, reassigns the second transmission to the third channel and assigns the first transmission corresponding to the multimedia network access message to the second channel When there is no available first channel and no second transmission which is moveable, the CMTS determines whether there is a third transmission on an assigned channel having a lower comparative priority than the comparative priority of the multimedia network access message, and when there is a third transmission, the CMTS removes the third transmission from the assigned channel to form a vacated channel, and assigns the transmission corresponding to the multimedia network access message to the vacated channel

Bus energy minimization by transition pattern coding (TPC) in deep sub-micron technologies

Abstract: The energy dissipation associated with driving long wires accounts for a significant fraction of the overall system energy. This is particularly the case with the increasing importance of the inter-wire parasitic capacitance in deep sub-micron technology. A closed form solution for estimating the energy dissipation of a data bus is presented that uses an elaborate parasitic wire model. This includes the distributed RLC effects of wires as well as the coupling between wires. We also propose a general class of coding techniques to reduce energy dissipation for data transmission by trading-off between computation and communication costs. An algorithm is presented to design efficient coding strategies to minimize energy. When the effects of inter-wire capacitance are taken into account, the best coding strategy is not to simply minimize transitions - an approach followed by previous research. Instead, Transition Pattern Coding (TPC) modifies the transition profile to minimize energy, and in many cases higher transition activity can result in lower energy. Results show that up to a factor of 2 reduction in energy.

Method and apparatus for executing secure data transfer in a wireless network

Abstract: A method for executing secure data transfer between a communication device (1) and an application server (5) in a wireless network (2, 3), wherein a request requiring a secure transaction of data is sent from ether the communication device (1) or the server (5) (303), an agreement proposal for the secure transaction is sent to the communication device (1) (304), if the agreement proposal is considered acceptable (305), the agreement proposal is sent to a security adapter (6) (306). Details of the transaction are entered into a message (308) and sent to a smart card in order to activate a signing application (309) in the smart card. The details of the transaction are displayed on the communication device (310), and if the transaction is accepted (311), the signing application signs the data and sends it to the security adapter (6) via messages (313), the signature is verified, and the data is sent to the server (315).