Patents Assigned to Telecommunications Research Laboratory
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Patent number: 7260059Abstract: Ongoing growth in transport demand is served while deferring or eliminating expenditure for additional capacity by reclaiming the protection capacity and inefficiently used working capacity in existing multi-ring network. Reclamation is through re-design of the routing and restoration in the network using mesh principles within the pre-existing ring capacities. The installed working and protection capacity of existing rings is viewed as a sunk investment, an existing resource, to be “mined” and incorporated into a mesh-operated network that serves both existing and ongoing growth. A complete double or even tripling of demand could be supported with little or no additional capacity investment through the period of ring-to mesh conversion by ring-mining. An existing ring set may be converted to a target architecture of “p-cycles” instead of a span-restorable mesh, through placement of straddling span interface units to convert ring ADMs to p-cycle nodal elements.Type: GrantFiled: June 28, 2002Date of Patent: August 21, 2007Assignee: Telecommunications Research LaboratoriesInventors: Wayne D. Grover, Matthieu Arnold Henri Clouqueur, Kwun Kit Leung
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Publication number: 20070115810Abstract: A method for restoring traffic in a network. The network includes plural distinct nodes interconnected by plural distinct spans, each span having working links and spare links. Each node has a digital cross-connect switch for making and breaking connections between adjacent spans forming span pairs at a node. Cross-connections between spare links in adjacent spans are made such that sets of successive nodes through which the adjacent spans form span paths form closed paths. A method of finding and construction closed paths is described in which statelets are broadcast through the network. In a preferred method of implementation of the method, the statelet broadcast occurs not in response to a network failure, but across the entire network before any particular span failure and may be carried out during normal network operations as a continual re-configuration of the network.Type: ApplicationFiled: January 23, 2007Publication date: May 24, 2007Applicant: TELECOMMUNICATIONS RESEARCH LABORATORIESInventors: Demetrios Stamatelakis, Wayne Grover
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Publication number: 20070016838Abstract: A method and an apparatus of constructing hybrid Automatic Repeat reQuest (ARQ) systems using specific properties of the BCJR error correcting algorithm. Since the convergence to an actual codeword is not always guaranteed with the BCJR, the method and apparatus implements a system, in which two different types of Negative AcKnowledgement messages (NAKs) are employed. The first type is the conventional one-bit NAK and the second type specifies retransmission pattern in such a way that the additional parity bits are concentrated on the parts of the code trellis that did not converge to a valid sequence.Type: ApplicationFiled: June 1, 2006Publication date: January 18, 2007Applicant: Telecommunications Research LaboratoriesInventors: Bartosz Mielczarek, Witold Krzymien
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Patent number: 7075892Abstract: A method of designing a telecommunications network, the method comprising the steps of A) for all working demand flows required to be routed in the telecommunications network, finding an initial topology of spans between nodes in the telecommunications network that is sufficient for routing all working demand flows, while attempting to minimize the cost of providing the spans; B) given the initial topology of spans identified in step A, finding a set of additional spans that ensures restorability of working demand flows that are required to be restored in case of failure of any span in the initial topology of spans, while attempting to minimize the cost of providing additional spans; and C) starting with the initial topology of spans and the additional spans identified in step B, finding a final topology of spans between nodes in the telecommunications network that attempts to minimize the total cost of the final topology of spans, while routing all working demand flows and ensuring restorability of working dType: GrantFiled: November 2, 2001Date of Patent: July 11, 2006Assignee: Telecommunications Research LaboratoriesInventors: Wayne D. Grover, John Doucette
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Patent number: 6996385Abstract: Channel coding is used on the forward link of a CDMA cellular telephone network to allow the CDMA mobile channel decoder to perform error correction. On a wireless link, channel code performance is improved by providing the channel decoder with an estimate of the reliability of each received symbol. This reliability information is typically the ratio of desired signal energy to interference plus noise variance at the channel decoder input. This invention improves CDMA mobile channel decoder performance using a new technique for calculating more accurate estimates of the signal to interference plus noise ratio at the input of the mobile channel decoder.Type: GrantFiled: September 27, 2002Date of Patent: February 7, 2006Assignee: Telecommunications Research LaboratoriesInventors: Geoffrey G. Messier, Witold A. Krzymien
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Patent number: 6970416Abstract: This invention is a wireless network based on orthogonal frequency division multiplexing (OFDM) and simple terminals. In a conventional OFDM system, the signal processing hardware is divided equally between the base station and the terminal. In this invention, most of the complex signal processing hardware is shifted to the base station, making the terminal a simpler and more power-efficient device. To send information to the base station, the terminal transmits a series of QPSK symbols that make up an OFDM-code. The code is designed to distribute the signal's energy into a number of OFDM sub-carriers which can be detected and combined within the base station's OFDM receiver. Other users transmit the same OFDM-codes within the same bandwidth and at the same time, but with slightly offset carrier frequencies. Because of the nature of OFDM, the codes from different users remain orthogonal, even in a multipath radio environment.Type: GrantFiled: July 7, 2000Date of Patent: November 29, 2005Assignee: Telecommunications Research LaboratoriesInventor: Grant McGibney
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Patent number: 6940893Abstract: This invention modulates data onto a radio channel in such a way that the deleterious effects of the channel are reduced. This is accomplished in three steps: first, the information signal is modulated using a phase-differential modulation scheme. Second, the modulated signal is spread in both time and frequency by passing it through a dispersive filter, transmitting it through the channel, and removing the spreading using a dispersive filter in the receiver with the opposite characteristics of the filter in the transmitter. The third step, after demodulation, is to pass the signal through a low-pass filter to gather up the signal energy which has been dispersed by the channel. All three of these steps can be implemented with simple functional blocks, making this system very inexpensive to implement. Also included are two methods for enhancing the data throughput of the basic system, making it more bandwidth efficient.Type: GrantFiled: September 27, 1999Date of Patent: September 6, 2005Assignee: Telecommunications Research LaboratoriesInventors: John A. Pinkney, Spence T. Nichols
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Patent number: 6914880Abstract: A method of configuring a node in an IP network by creating a set of router table entries which form a set of virtually preconfigured cyclical routes, or p-cycles, within the IP network. This set of p-cycles is virtual in the sense that the only resources which they normally consume are routing table entries. No transmission capacity is required for them, unless/until they are used to carry packets (traffic.) These p-cycles sit idle and unused until a failure takes place. The routers surrounding the failure then use these p-cycles to route packets, which normally would be lost, around the failure. A router having an entry in its router table identifying the p-cycle, together with an associated port, is also disclosed, and also a data packet that may use a p-cycle to get to its destination.Type: GrantFiled: May 19, 1999Date of Patent: July 5, 2005Assignee: Telecommunications Research LaboratoriesInventors: Wayne D. Grover, Demetrios Stamatelakis
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Patent number: 6889060Abstract: A Fiber-wireless uplink consists of a wireless channel followed by a radio-over-fiber (ROF) link. Typically, nonlinear distortion of the ROF link is the major concern when the radio frequency is only a few GHz. This especially severe in the uplink, because of the multipath fading of the wireless channel. A Hammerstein type decision feedback equalizer is described for the fiber wireless uplink, that compensates for nonlinear distortion of the ROF link as well as linear dispersion of the wireless channel. Since the linear and nonlinear parts of the receiver are separated, tracking the fast changing wireless channel is virtually independent of compensating for the relatively static nonlinearity. Analytical results show that the receiver provides excellent compensation with notably less complexity.Type: GrantFiled: April 29, 2002Date of Patent: May 3, 2005Assignee: Telecommunications Research LaboratoriesInventors: Xavier Navajothy Fernando, Abu Bakarr Sesay
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Patent number: 6873750Abstract: An electro-optic modulator structure for particular use in narrowband optical subcarrier systems. A traveling wave is established across the active region of the device, instead of a standing wave. This is accomplished through the use of a directional resonator structure that prevents reverse-traveling waves from being established within the resonator. Hence, the electric field is applied to the traveling optical wave in a similar fashion to a traveling-wave modulator, except that the traveling wave has a much greater amplitude due to the build-up of energy inside the resonator. Since the modulator is operated in a traveling-wave fashion, it can be tuned to operate at any frequency using tuning elements, regardless of the length of the active region. Furthermore, the microwave and optical signals can be velocity-matched to mitigate optical transit time effects that are normally associated with a resonant modulator utilizing a standing-wave electrode structure.Type: GrantFiled: March 12, 2003Date of Patent: March 29, 2005Assignee: Telecommunications Research LaboratoriesInventors: Sean V. Hum, Robert J. Davies, Michal Okoniewski
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Patent number: 6822434Abstract: A monolithic transformer compensated circuit with enhanced quality factor without significantly increasing noise levels is presented in this disclosure. The technique uses a monolithic transformer and a current source driving current into the transformer secondary winding to achieve loss compensation in the transformer primary. An ac current which is proportional to, and in phase with the voltage applied to the primary winding can be used to achieve theoretically perfect loss compensation at a given frequency in the RF (GHz) frequency range. Examples of circuit applications that are particularly suited to the technique include Voltage Controlled Oscillators (VCO's), Low Noise Amplifiers (LNA's) and Filters. The technique has the added advantage of reducing power consumption in some applications.Type: GrantFiled: January 28, 2003Date of Patent: November 23, 2004Assignee: Telecommunications Research LaboratoriesInventors: James William Haslett, Bogdan Alexandru Georgescu, John Godfrey McRory, Holly Evelyn Pekau
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Patent number: 6819662Abstract: A method of connecting a telecommunications network, in which the network is formed of plural nodes connected by plural spans. Each node has a nodal switching device for making connections between adjacent spans meeting at the node. Method steps A-F are followed. A) Select a set of candidate rings, each candidate ring being formed of nodes connected by spans, the candidate rings each being capable of serving a number of demands and having a ring construction cost C. B) Assess the total transport utility U of each candidate ring, wherein the total transport utility is a measure of at least the number of demands served by the respective candidate ring. C) Assess the construction cost of each candidate ring. D) Calculate a ratio formed of U/C for each candidate ring. E) Choose, from the set of candidate rings, a best set of candidate rings, wherein candidate rings in the best set of candidate rings have a higher ratio of U/C than candidate rings not in the best set.Type: GrantFiled: April 28, 2000Date of Patent: November 16, 2004Assignee: Telecommunications Research LaboratoriesInventors: Wayne D. Grover, G. Dave Morley, James B. Slevinsky
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Publication number: 20040223655Abstract: Compact and efficient hardware architectures for implementing lifting-based DWTs, including 1-D and 2-D versions of recursive and dual scan architectures. The 1-D recursive architecture exploits interdependencies among the wavelet coefficients by interleaving, on alternate clock cycles using the same datapath hardware, the calculation of higher order coefficients along with that of the first-stage coefficients. The resulting hardware utilization exceeds 90% in the typical case of a 5-stage 1-D DWT operating on 1024 samples. The 1-D dual scan architecture achieves 100% datapath hardware utilization by processing two independent data streams together using shared functional blocks. The 2-D recursive architecture is roughly 25% faster than conventional implementations, and it requires a buffer that stores only a few rows of the data array instead of a fixed fraction (typically 25% or more) of the entire array.Type: ApplicationFiled: May 9, 2003Publication date: November 11, 2004Applicant: Telecommunications Research LaboratoriesInventors: Hongyu Liao, Mrinal K. Mandal, Bruce F. Cockburn
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Publication number: 20040179631Abstract: This disclosure document outlines the concept and description of a Rake receiver with single bit detection processing optimized for the reception of UWB (Ultra_WideBand) signals. The propagation channel estimation required by the Rake receiver is achieved by estimating the probability density function of the single bit quantizer output rather than using a complex analog amplitude estimation which typically requires multi-bit detector quantization and significantly more processing. As only a single quantization bit is used, the quantity of Digital Signal Processing (DSP) operations required per received data bit is drastically reduced. This has advantages in reducing the processing power and cost requirements.Type: ApplicationFiled: March 12, 2004Publication date: September 16, 2004Applicant: Telecommunications Research LaboratoriesInventor: Jorgen Staal Nielsen
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Patent number: 6791473Abstract: A Smart Parking Meter System makes it possible to track whether or not a vehicle occupies parking meter stalls and whether or not the time has expired. The system uses a wireless communication protocol which may be of the type known under the trade mark “Bluetooth” and provides the portability of embedded systems and the convenience of personal digital assistants with the powers of the C and Java programming languages. There are two main components to the Smart Parking Meter System, the handheld device, or the PDA, and the actual parking meters. Each device has the Smart Parking Meter System application installed in it, as well as the wireless modules, such as Bluetooth to use as a communication medium. The parking meters also have a motion sensor to detect any movement within it view range. The handheld device is able to extract all the parking states for each parking meter within a block or street depending on user configuration of system.Type: GrantFiled: December 2, 2002Date of Patent: September 14, 2004Assignee: Telecommunications Research LaboratoryInventors: Sami Kibria, Joseph Chai-Wan Wu, Jose Alejandro Rueda, Nicholas Christopher Wade Thiessen, Christopher Troy Kavanagh, Paul Serge Card
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Patent number: 6765708Abstract: An apparatus for modulating information bearing symbols onto an optical carrier includes a polybinary coder that operates on a binary information signal to produce an envelope compatible polybinary signal; and an optical single sideband modulator that modulates an optical carrier with the envelope compatible polybinary signal to produce a single sideband optical signal. This provides an improvement over both polybinary signaling and optical single sideband. This action combines the chromatic dispersion advantages of SSB modulation with the DC level and bandwidth reduction of duo-binary coding.Type: GrantFiled: January 21, 2003Date of Patent: July 20, 2004Assignee: Telecommunications Research LaboratoriesInventor: Robert James Davies
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Publication number: 20040133663Abstract: A simple and effective pre-processing step to reduce the complexity of solving p-cycle network design problems involving pre-selecting candidate cycles based on their topological score (TS) and a priori efficiency (AE) is disclosed. The disclosure contains a case study that examines joint optimization of working routes with placement of p-cycles.Type: ApplicationFiled: July 2, 2003Publication date: July 8, 2004Applicant: Telecommunications Research Laboratories.Inventors: Wayne D. Grover, John Doucette
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Publication number: 20040109407Abstract: This disclosure introduces a significant extension to the method of p-cycles for network protection. The main advance is the generalization of the p-cycle concept to protect multi-span segments of contiguous working flow, not only spans that lie on the cycle or directly straddle the p-cycle. This effectively extends the p-cycle technique to include path protection, or protection of any flow segment along a path, as well as the original span protecting use of p-cycles. It also gives an inherent means of transit flow protection against node loss. We present a capacity optimization model for the new scheme and compare it to prior p-cycle designs and other types of efficient mesh-survivable networks. Results show that path-segment-protecting p-cycles (“flow p-cycles” for short) have capacity efficiency near that of a path-restorable network without stub release.Type: ApplicationFiled: July 14, 2003Publication date: June 10, 2004Applicant: Telecommunications Research Laboratories.Inventors: Wayne D. Grover, Ganxiang Shen
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Patent number: 6741643Abstract: This disclosure covers a method of equalization for a high speed, indoor wireless local area network. The invention is designed so that the terminal equipment is as simple as possible while the hardware required for adaptive filtering, antenna diversity and frequency diversity is implemented almost entirely at the base station. The system uses pre-equalization for the downlink and post-equalization for the uplink. Antenna diversity and adaptive rate frequency diversity are used together to reduce the effects of frequency selective multipath fading to ensure that the equalizer can correct the distortion introduced by the radio channel.Type: GrantFiled: April 15, 1998Date of Patent: May 25, 2004Assignee: Telecommunications Research LaboratoriesInventor: Grant McGibney
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Patent number: 6734712Abstract: A parallel-summation logarithmic amplifier is described that uses a novel topology of cascaded and parallel amplifiers to achieve extremely high bandwidth. Included in the topology is a unique delay matching scheme for logarithmic amplifiers that is amenable to fabrication in integrated circuit form. The result is flat group delay over broad frequency ranges and different power levels. The resulting log amplifier is suitable for radar applications and for use in high data rate fiber-optic networks. Also described is a unique design process that yields a set of amplifier gains that closely approximate a logarithm. Also described is the novel idea of using a parallel feedback amplifier (PFA) in piecewise-approximate logarithmic amplifiers. This innovation allows for the design of broadband amplifiers with significantly different gains and similar phase characteristics, which is extremely useful when designing high-frequency logarithmic amplifiers.Type: GrantFiled: May 24, 2002Date of Patent: May 11, 2004Assignee: Telecommunications Research LaboratoriesInventors: Christopher D. Holdenried, James W. Haslett, John G. McRory, Robert J. Davies