Showing papers on "Communications system published in 2007"

Radio communication system

Abstract: PROBLEM TO BE SOLVED: To suppress wiring costs even if there is an area that can not be watched from a base station device, by utilizing a radio repeater station, to construct a radio system wherein useless traffic is not generated, by utilizing a route control table and further, to also deal with the movement of a radio terminal device. SOLUTION: Regarding a base station device 24, a radio relay station 40 and a radio terminal device 26 existent under control of an information transfer apparatus 22 itself, the information transfer apparatus 22 stores in a table storage section 22a the relation between layer-3 addresses of the devices and its own communication port 28-i to which those devices are connected. Therefore, a communication port 28-i for outputting is determined in accordance with the layer-3 destination address of a packet, and the packet can be outputted from the communication port 28-i. If the radio terminal device 26 moves, the information transfer apparatus 22 and the radio relay station 40 then rewrite their tables. COPYRIGHT: (C)2008,JPO&INPIT

Telephony control system with intelligent call routing

Abstract: A system and method for communicating in a communication network, comprising presenting a communication comprising data over a communications network to a router, said router being adapted to route the communication to one of a plurality of available network destinations; automatically executing a communication targeting algorithm in the router, based at least in part on the data, wherein the communication targeting algorithm operates to contextually jointly analyze a plurality of parameters extracted from the data and a plurality of contextual parameters, to determine an optimum target for the communication, wherein the optimum target varies in dependence on both the data and the context of the communication; and routing the communication in dependence on the algorithm execution.

Communication system and communication apparatus

Abstract: A communication system includes the following elements: a transmitter including a transmission circuit unit configured to generate an RF signal for transmitting data and an electric-field-coupling antenna configured to transmit the RF signal as an electrostatic field; a receiver including an electric-field-coupling antenna and a reception circuit unit configured to receive and process the RF signal received by the electric-field-coupling antenna; and a surface-wave propagation medium configured to provide a surface-wave transmission line to transmit a surface wave emanating from the electric-field-coupling antenna of the transmitter with low propagation loss.

Short-Range Ultra-Broadband Terahertz Communications: Concepts and Perspectives

Abstract: We propose the concept of ultra-broadband terahertz communication, based on directed non-line-of-sight (NLOS) transmissions. Potential applications of such a system supporting multi-gigabit data rates are given, and put into the context of currently emerging WLANs/WPANs. The technology and propagation constraints serve as boundary conditions for the determination of the required antenna gain to support ultra-broadband communication. Resulting high-gain antenna requirements will necessitate highly directed transmissions. We propose the use of omni-directional dielectric mirrors to support directed NLOS paths. Their performance is investigated with ray-tracing simulations of a terahertz propagation channel in a dynamic office environment, which is calibrated with measured building-material and mirror parameters. We demonstrate that a directed NLOS path scheme will make a terahertz communication system robust to shadowing. Furthermore, we show that dielectric mirrors covering only parts of the walls will significantly enhance the signal coverage in a typical indoor scenario.

System and method for routing data on a packet network

Abstract: The disclosed embodiments include system and method for routing communications over a communications network. In one embodiment, a determination is made as to whether to establish a communication along a communication path based on network performance information. The disclosed embodiments provide several alternatives for establishing the communication and improving communications along the communication path in response to a determination that at least one network node along the communication path is impaired or congested.

Photonic Generation of Ultrawideband Signals

Abstract: Ultrawideband (UWB) that is regulated by the Federal Communications Commission (FCC) for short-range high-throughput wireless communication and sensor networks with advantageous features, such as immunity to multipath fading, extremely short time duration, being carrier free, and having low duty cycle, wide bandwidth, and low power spectral density, has been a topic of interest recently. By wireless transmission, UWB communications systems can only operate in a short distance of a few meters to tens of meters. The convergence of UWB and optical fiber distribution techniques, or UWB over fiber, offers the availability of undisrupted service across different networks and eventually achieves high-data-rate access at any time and from any place. To distribute the UWB signals over the optical fiber, it is also desirable that the UWB signals can be generated in the optical domain without having extra electrical-to-optical conversion. In addition, UWB signals that are generated in the optical domain can be easily tailored to have a spectrum that meets the FCC-specified spectral mask. In this paper, techniques to generate UWB signals in the optical domain will be discussed. These techniques are divided into three categories, with the generation of UWB signals based on the following: 1) phase-modulation-to-intensity-modulation conversion; 2) a photonic microwave delay-line filter; and 3) optical spectral shaping and dispersion-induced frequency-to-time mapping. The areas for future development and the challenge of implementation of these techniques for practical applications will also be discussed.

Mimo Transceiver Design Via Majorization Theory

Abstract: Multiple-input multiple-output (MIMO) channels provide an abstract and unified representation of different physical communication systems, ranging from multi-antenna wireless channels to wireless digital subscriber line systems. They have the key property that several data streams can be simultaneously established. In general, the design of communication systems for MIMO channels is quite involved (if one can assume the use of sufficiently long and good codes, then the problem formulation simplifies drastically). The first difficulty lies on how to measure the global performance of such systems given the tradeoff on the performance among the different data streams. Once the problem formulation is defined, the resulting mathematical problem is typically too complicated to be optimally solved as it is a matrix-valued nonconvex optimization problem. This design problem has been studied for the past three decades (the first papers dating back to the 1970s) motivated initially by cable systems and more recently by wireless multi-antenna systems. The approach was to choose a specific global measure of performance and then to design the system accordingly, either optimally or suboptimally, depending on the difficulty of the problem. This text presents an up-to-date unified mathematical framework for the design of point-to-point MIMO transceivers with channel state information at both sides of the link according to an arbitrary cost function as a measure of the system performance. In addition, the framework embraces the design of systems with given individual performance on the data streams. Majorization theory is the underlying mathematical theory on which the framework hinges. It allows the transformation of the originally complicated matrix-valued nonconvex problem into a simple scalar problem. In particular, the additive majorization relation plays a key role in the design of linear MIMO transceivers (i.e., a linear precoder at the transmitter and a linear equalizer at the receiver), whereas the multiplicative majorization relation is the basis for nonlinear decision-feedback MIMO transceivers (i.e., a linear precoder at the transmitter and a decision-feedback equalizer at the receiver).

On the Design of a Photonic Network-on-Chip

Abstract: Recent remarkable advances in nanoscale silicon-photonic integrated circuitry specifically compatible with CMOS fabrication have generated new opportunities for leveraging the unique capabilities of optical technologies in the on-chip communications infrastructure. Based on these nano-photonic building blocks, we consider a photonic network-on-chip architecture designed to exploit the enormous transmission bandwidths, low latencies, and low power dissipation enabled by data exchange in the optical domain. The novel architectural approach employs a broadband photonic circuit-switched network driven in a distributed fashion by an electronic overlay control network which is also used for independent exchange of short messages. We address the critical network design issues for insertion in chip multiprocessors (CMP) applications, including topology, routing algorithms, path-setup and tear-down procedures, and deadlock avoidance. Simulations show that this class of photonic networks-on-chip offers a significant leap in the performance for CMP intrachip communication systems delivering low-latencies and ultra-high throughputs per core while consuming minimal power

Apparatus and method using near field communications

Abstract: A near field communications enabled mobile communication is used to provide or receive information.

Vehicle diagnostic or prognostic message transmission systems and methods

Abstract: System and method for monitoring the condition of a vehicle includes a communications unit arranged to interface with a wireless communications network, at least one sensor for monitoring at least one component or subsystem of the vehicle and which is coupled to the communications unit, and a remote site connected to the wireless communications network and arranged to receive diagnostic or prognostic messages from the vehicle with the transmission initiated therefrom A diagnostic module may be provided, included or coupled to the sensor(s) and directs the communications unit to transmit a message to the remote site upon determining an actual and/or potential failure of a component or subsystem

Automatic security action invocation for mobile communications device

Abstract: A mobile communications device, server, communications system, computer program product, and method for providing security on a mobile communications device are described. In accordance with one example embodiment, the mobile communications device comprises: a processor; a communications subsystem connected to the processor operable to exchange signals with a wireless network and with the processor; a storage element connected to the processor and having a plurality of application modules and data stored thereon, the data comprising at least user application data associated with the application modules and service data including data for establishing communications with the wireless network; and a security module operable to detect policy messages received by the mobile communications device; wherein the security module is further operable to perform a security action if a first policy message to enforce a first data protection policy is received and a subsequent policy message to enforce a second data protection policy is not received within a predetermined duration from a time at which the first policy message is received; and wherein the security action comprises erasing or encrypting at least some of the data on the storage element.

Voice communication system and voice communication method

Abstract: A voice communication system, which is connected to a LAN to which communication terminals are connected and to a public network to which telephones are connected, is provided with a communication server between the LAN and public network having different protocols from each other. The communication server enables a voice communication between a telephone on the public network and a communication terminal connected to the LAN by performing processing similar to that for a voice communication between two communication terminals connected to the LAN. The communication server determines whether an address of the other party inputted by a user is a communication terminal address or a telephone number, and transmits a voice communication request to a communication terminal of the other party when the address is a communication terminal address. When the address is a telephone number, the user acquires the communication terminal address of the communication server, and transmits a voice communication request to the communication server. Thereafter, the voice communication processing is performed through the communication server.

Network Flow Watermarking Attack on Low-Latency Anonymous Communication Systems

Abstract: Many proposed low-latency anonymous communication systems have used various flow transformations such as traffic padding, adding cover traffic (or bogus packets), packet dropping, flow mixing, flow splitting, and flow merging to achieve anonymity. It has long been believed that these flow transformations would effectively disguise net-workflows, thus achieve good anonymity. In this paper, we investigate the fundamental limitations of flow transformations in achieving anonymity, and we show that flow transformations do not necessarily provide the level of anonymity people have expected or believed. By injecting unique watermark into the inter-packet timing domain of a packet flow, we are able to make any sufficiently long flow uniquely identifiable even if I) it is disguised by substantial amount of cover traffic, 2) it is mixed or merged with a number of other flows, 3) it is split into a number subflows, 4) there is a substantial portion of packets dropped, and 5) it is perturbed in timing due to either natural network delay jitter or deliberate timing perturbation. In addition to demonstrating the theoretical limitations of low-latency anonymous communications systems, we develop the first practical attack on the leading commercial low-latency anonymous communication system. Our real-time experiments show that our flow watermarking attack only needs about 10 minutes active Web browsing traffic to "penetrate" the total net shield service provided by www.anonymizer.com. Our analytical and empirical results demonstrate that achieving anonymity in low-latency communication systems is much harder than we have realized, and current flow transformation based low-latency anonymous communication systems need to be revisited.

Method of addressing messages and communications system

Abstract: A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising combining tree search and Aloha methods to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision. A system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator in a wireless fashion, the respective wireless identification devices having a unique identification number, the interrogator being configured to employ tree search and Aloha techniques to determine the unique identification numbers of the different wireless identification devices so as to be able to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision by multiple wireless identification devices attempting to respond to the interrogator at the same time.

Distributed antenna communications system

Abstract: A distributed antenna system comprises a base transceiver station, a plurality of distributed antenna units and a signal routing apparatus. The base transceiver station has a plurality of output ports that generate a plurality of downlink signals having overlapping transmit frequencies and containing different communication content. The different communication content is directed toward each of a plurality of mobile units. The base transceiver station also has at least one uplink receive port that receives an uplink signal. The uplink signal includes communication content received from at least one of the mobile units. The plurality of distributed antenna units have coverage areas that are non-overlapping or only partially overlapping. The signal routing apparatus routes the downlink signals to the plurality of distributed antennas such that each of the plurality of downlink signals are transmitted by one or more of the distributed antennas and each distributed antenna only transmits one of the downlink signals.

Remote monitoring and control system

Abstract: A communication system that provides communication of information between an end user device and a remote end user. The system includes a communication node mounted on the upper part of a utility pole, and drawing its power from the utility pole through a standard NEMA Locking 3 Pole Receptacle, and adapted to communicate with a nearby user device using the low-power communication protocol, such as the ZigBee protocol (ANSI IEEE 802.15.4) or Radio Frequency Identification Device (RFID) technology, and also adapted to communicate with a neighborhood mesh network of nodes mounted on utility poles. The neighborhood mesh network is capable of communicating, through a regional computer network, with the remote end user.

Chaos Applications in Telecommunications

Abstract: Introduction Peter Stavroulakis Chaotic Signal Generation and Transmission Antonio Candido Faleiros,Waldecir Joao Perrella,Tania Nunes Rabello,Adalberto Sampaio Santos, and NeiYoshihiro Soma Chaotic Transceiver Design Arthur Fleming-Dahl Chaos-Based Modulation and Demodulation Techniques Francis CM Lau and Chi K Tse A Chaos Approach to Asynchronous DS-CDMA Systems S Callegari, G Mazzini, R Rovatti, and G Setti Channel Equalization in Chaotic Communication Systems Mahmut Ciftci Optical Communications using Chaotic Techniques Gregory D VanWiggeren APPENDIX A Fundamental Concepts of the Theory of Chaos and Fractals Tassos Bountis APPENDIX B Mathematical Models of Chaos Christos H Skiadas

Method and apparatus for resource management

Abstract: Some embodiments are implemented in a communication system that includes a first wireless communication system and a second wireless communication system that includes a Femtocell access point (FAP) and a network controller that can communicatively couple the FAP to the first wireless communication system. In some embodiments, the network controller can communicatively couple to the first wireless communication system through a UTRAN Iu interface. Some embodiments provide a resource management method that determines that a user equipment (UE) has roved in a region serviced by the FAP. The FAP includes a generic access resource control (GA-RC) protocol sub-layer. The method creates a separate GA-RC state dedicated to the UE in the GA-RC protocol sub-layer. The method also sets the GA-RC state dedicated to the UE to a deregistered state to indicate that the UE is not registered to use the services of the second wireless communication system.

System for and method of configuring distributed antenna communications system

Abstract: A distributed antenna system comprises a plurality of antennas and a multi-port hub. The multi-port hub comprises an interface to a telecommunications network and a plurality of transceivers. The multi-port hub is configured to operate in a first mode ('normal' mode) in which the multi-port hub receives a downlink communications signal via the interface and distributes the downlink communications signal to the plurality of antennas using a selected downlink transmission frequency within a downlink frequency range and in which the multi-port hub receives uplink communications signals from the plurality of antennas at a selected uplink receive frequency. The multi-port hub is also configured to operate in a second mode ('listening' mode) in which the multi-port hub receives communications signals from the plurality of antennas at one or more frequencies within the downlink frequency range. The transmission frequency for the first mode ('normal' mode) may be selected based on field strength of the signals received in the second mode ('listening' mode).

A high-frequency warm shallow water acoustic communications channel model and measurements

Abstract: Underwater acoustic communication is a core enabling technology with applications in ocean monitoring using remote sensors and autonomous underwater vehicles. One of the more challenging underwater acoustic communication channels is the medium-range very shallow warm-water channel, common in tropical coastal regions. This channel exhibits two key features—extensive time-varying multipath and high levels of non-Gaussian ambient noise due to snapping shrimp—both of which limit the performance of traditional communication techniques. A good understanding of the communications channel is key to the design of communication systems. It aids in the development of signal processing techniques as well as in the testing of the techniques via simulation. In this article, a physics-based channel model for the very shallow warm-water acoustic channel at high frequencies is developed, which are of interest to medium-range communication system developers. The model is based on ray acoustics and includes time-varying statistical effects as well as non-Gaussian ambient noise statistics observed during channel studies. The model is calibrated and its accuracy validated using measurements made at sea.

Acoustic propagation considerations for underwater acoustic communications network development

Abstract: The underwater environment is widely regarded as one of the most difficult communication channels. Underwater acoustic communications systems are challenged by the characteristics of acoustic propagation through the underwater environment. There are a wide range of physical processes that impact underwater acoustic communications and the relative importance of these processes are different in different environments. In this paper some relevant propagation phenomena are described in the context of how they impact the development and/or performance of underwater acoustic communications networks. The speed of sound and channel latency, absorption and spreading losses, waveguide effects and multipath, surface scattering, bubbles, and ambient noise are all briefly discussed.

Peak Power Control in Multicarrier Communications

Abstract: Peak signal power is an important factor in the implementation of multicarrier (MC) modulation schemes, like OFDM, in wireless and wireline communication systems. This 2007 book describes tools necessary for analyzing and controlling the peak-to-average power ratio in MC systems, and how these techniques are applied in practical designs. The author starts with an overview of multicarrier signals and basic tools and algorithms, before discussing properties of MC signals in detail: discrete and continuous maxima; statistical distribution of peak power; codes with constant peak-to-average power ratio are all covered, concluding with methods to decrease peak power in MC systems. Current knowledge, problems, methods and definitions are summarized using rigorous mathematics, with an overview of the tools for the engineer. The book is aimed at graduate students and researchers in electrical engineering, computer science and applied mathematics, and practitioners in the telecommunications industry.

Voice-controlled communications system and method using a badge application

Abstract: A communication system has a control computer, one or more concentrators and one or more access device each having a badge application that communicates wirelessly with the one or more concentrators. The access device with the badge application provides the user with a communications device that permits the user to initiate telephone calls and conferences, receive telephone calls, receive pages and be located within a particular environment.

Quality-of-service driven power and rate adaptation for multichannel communications over wireless links

Abstract: We propose a quality-of-service (QoS) driven power and rate adaptation scheme for multichannel communications systems over wireless links. In particular, we use multichannel communications to model the conceptual architectures for either diversity or multiplexing systems, which play a fundamental role in physical-layer evolutions of mobile wireless networks. By integrating information theory with the concept of effective capacity, our proposed scheme aims at maximizing the multichannel-systems throughput subject to a given delay-QoS constraint. Under the framework of convex optimization, we develop the optimal adaptation algorithms. Our analyses show that when the QoS constraint becomes loose, the optimal power-control policy converges to the well-known water-filling scheme, where the Shannon (or ergodic) capacity can be achieved. On the other hand, when the QoS constraint gets stringent, the optimal policy converges to the scheme operating at a constant-rate (i.e., the zero-outage capacity), which, by using only a limited number of subchannels, approaches the Shannon capacity. This observation implies that the optimal effective capacity function decreases from the ergodic capacity to the zero-outage capacity as the QoS constraint becomes more stringent. Furthermore, unlike the single-channel communications, which have to trade off the throughput for QoS provisioning, the multichannel communications can achieve both high throughput and stringent QoS at the same.

Vehicle communication system

Abstract: A vehicle communication system detects the presence of a passenger wearable communication device. The system receives audio signals from multiple sources inside or outside of a vehicle. The system processes the signals before routing the signals to multiple destinations. The destinations may include wearable personal communication devices, front and/or rear speakers, and/or a remote mobile device.

Method and apparatus for user equipment registration

Abstract: Some embodiments are implemented in a communication system that includes a first wireless communication system and a second wireless communication system that includes a Femtocell access point (FAP) and a network controller that can communicatively couple the FAP to the first wireless communication system. In some embodiments, the network controller can communicatively couple to the first wireless communication system through a UTRAN Iu interface. In some embodiments, the FAP can communicatively couple to a user equipment using a short-range licensed wireless frequency. Some embodiments provide a method of performing a user equipment (UE) registration. The method establishes a unique connection dedicated to the UE between the FAP and the network controller. The method receives a register request message at the network controller from the FAP through the dedicated connection.

A System Level Energy Model and Energy-Quality Evaluation for Integrated Transceiver Front-Ends

Abstract: As CMOS technology scales down, digital supply voltage and digital power consumption goes down. However, the supply voltage and power consumption of the RF front-end and analog sections do not scale in a similar fashion. In fact, in many state-of-the-art communication transceivers, RF and analog sections can consume more energy compared to the digital part. In this paper, first, a system level energy model for all the components in the RF and analog front-end is presented. Next, the RF and analog front-end energy consumption and communication quality of three representative systems are analyzed: a single user point-to-point wireless data communication system, a multi-user code division multiple access (CDMA)-based system and a receive-only video distribution system. For the single user system, the effect of occupied signal bandwidth, peak-to-average ratio (PAR), symbol rate, constellation size, and pulse-shaping filter roll-off factor is analyzed; for the CDMA-based multi-user system, the effect of the number of users in the cell and multiple access interference (MAI) along with the PAR and filter roll-off factor is studied; for the receive-only system, the effect of 1/f noise for direct-conversion receiver and the effect of IF frequency for low-IF architecture on the RF front-end power consumption is analyzed. For a given communication quality specification, it is shown that the energy consumption of a wireless communication front-end can be scaled down by adjusting parameters such as the pulse shaping filter roll-off factor, constellation size, symbol rate, number of users in the cell, and signal center frequency

Radio Frequency Integrated Circuits and Technologies

Abstract: The operation frequencies, bandwidths and data capacities of communications systems are continuously increasing by employing advanced technologies and aggressive scaling of device dimensions. However, the restrictions inherent in scaling make the design of radio frequency integrated circuits a demanding task. To meet the corresponding challenges designers must provide profound skills in several areas including circuit theory, silicon and compound semiconductor technologies, communications standards, system design, measurement techniques, etc. The book aims at addressing all these multidisciplinary issues in a compact and comprehensive form and in a single volume. Suitable for students, engineers and scientists, the manuscript offers the necessary theoretical background together with cookbook-like optimisation strategies and state-of-the-art design examples.

System and apparatus for maintaining a communication system

Abstract: A system and apparatus for maintaining a communication system is disclosed. An apparatus that incorporates teachings of the present disclosure may include, for example, a computer-readable storage medium in a maintenance server of a communication system, comprising computer instructions for monitoring for installed components in interconnected Digital Subscriber Line (DSL) networks of the communication system based at least in part on provisioning records for each of the interconnected DSL networks, filtering telemetry and maintenance data associated with the installed components in the interconnected DSL networks according to criteria comprising actual criteria and predictive criteria, monitoring for a fault in the installed components based at least in part on the telemetry and maintenance data associated with the actual criteria, and predicting a potential fault in the installed components based at least in part on the telemetry and maintenance data associated with the predictive criteria. Additional embodiments are disclosed.

Communication system and method for narrowcasting

Abstract: A communication system with client devices in communication with at least one communication network. User data stores are also in communication with the communications network and store user data of users using respective ones of the client devices. Offer data stores also in communication with the communications network store offers from merchants. A narrowcasting engine includes an active data gathering module to collect the user data, and an active learning module to generate a user profile based on the user data. The communication engine selects dynamically offers from the offer data store based on the profile, and communicates the selected offers in the offer data store to the users.