Abstract: A fiber optic network transmits data between a hub node and a plurality of local nodes connected by at least one unidirectional fiber ring. Downstream data streams are carried on wavelength-division-multiplexed optical carriers from the hub node to the local nodes. An optical carrier corresponding to a specific wavelength carries downstream data streams to a specific local node. Downstream data streams are multiplexed onto an optical carrier via orthogonal frequency division multiplexing. A parallel signal detector in each local node detects all downstream optical carriers. A signal processing module demultiplexes the data stream from the optical carrier having the specific wavelength corresponding to the local node. An upstream data stream is multiplexed via orthogonal frequency division multiplexing onto an upstream optical carrier having the same specific wavelength and transmitted from the local node to the hub node. Upstream data awaiting transmission is allocated to specific subcarriers and time slots.

Abstract: A method includes generating an optical millimeter wave signal for modulation of a first data signal, and deriving from the generated optical millimeter wave signal a subsequent light source for modulation of a second data signal. More specifically the generating includes modulating a light wave to a multiple of a frequency of an oscillating signal. Alternatively, the generating includes modulating a data signal mixed with an oscillating signal to a multiple of a frequency of the oscillating signal. The deriving includes modulating a frequency component filtered from a data modulation of the generated optical millimeter wave signal.

Abstract: An apparatus includes an interleaver configuration for at least one of combining or separating odd and even channel groups to achieve channel density doubling; and an optical equalizer for suppressing inter symbol interference within the channels to provide intra-channel equalizing in the optical path, the equalizer being integrated into the interleaver. Preferably, optical equalizer and interleaver are integrated together as a single monolithic device, the optical equalizer includes a passband that has a dip in the channel center to achieve a raised-cosine filtering profile in the optical signal path to achieve inter-symbol interference ISI suppression, and the equalizer includes integration into the optical path of the interleaver to realize a monolithic device combining or separating odd and even channel groups to achieve channel density doubling.

Abstract: Systems and method are disclosed for applying a query to an event stream by storing one or more event constraints; performing constraint aware complex event processing on the query and the event constraints; and optimizing the query at run time.

Abstract: Packet transmission is performed in a wireless adaptive hybrid automatic repeat request transmission system. An optimized assignment rate for a packet is determined based at least in part on a maximal number of transmission attempts and a long term signal to noise ration of the wireless transmission system, an optimized quadrature amplitude modulation set is determined for the packet based at least in part on the maximal number of transmission attempts and the long term signal to noise ration of the wireless transmission system, and information related to the packet is transmitted based at least in part on the determined optimized assignment rate and determined optimized quadrature amplitude modulation set.

Abstract: A method includes generating at least two lightwave carriers from a lightwave source, the carriers having a wavelength spacing, creating an up-subchannel and a down-subchannel orthogonal to one another and spaced apart based on the fixed wavelength spacing from modulations of the lightwave carriers according to respective up-converted OFDM signals that are carrier suppressed, and combining one lightwave from the up-subchannel and one lightwave from the down-subchannel into an optical channel for transmission over an optical fiber.

Abstract: Multi-user (MU-) MIMO systems with quantized feedback are designed to maximize the sum-rate via scheduling and linear precoding. To maximize throughput over the network, quantized CSIT is sent through a low-rate feedback link feedback from a plurality of users back to a base station. The base station then determines a subset of the plurality of users to transmit one or more signals to based on the received feedback and determines a preceding matrix based on the received feedback from the plurality of users wherein the precoding matrix maximizes a sum-rate throughput for the subset of the plurality of users. Additionally, based on the received feedback, the base station designs a quantization codebook. This codebook may be designed off-line and/or online. The codebook and/or precoding matrix are used to transmit signals to the users.

Abstract: A method for filtering in a wireless downlink channel, where all dominant transmitting sources use inner codes from a particular set, includes the steps of estimating a channel matrix seen from a desired transmitter source in response to a pilot or preamble signal; converting the estimated channel matrix into an effective channel matrix responsive to the inner code of the desired transmitting source; estimating a covariance matrix of noise plus interference in a linear model whose output is an equivalent of the received observations and in which the effective channel matrix corresponding to each dominant transmitting source inherits the structure of its inner code; computing a signal-to-noise-interference-ratio SINR responsive to the covariance matrix and the effective channel matrix corresponding to the desired source; and feeding back the computed SINR to the transmitter source.

Abstract: A method for decoding and rate assignment in a wireless channel, where all dominant transmitter sources use inner codes from a particular set, comprising the steps of: i) estimating channel matrices seen from all dominant transmitter sources in response to a pilot or preamble signal transmitted by each such source; ii) converting each estimated channel matrix into an effective channel matrix responsive to the inner code of the corresponding transmitter source; iii) obtaining the received observations in a linear equivalent form (linear model) whose output is an equivalent of the received observations and in which the effective channel matrix corresponding to each dominant transmitter source inherits the structure of its inner code; iv) processing the transmitter sources according to the specified (or pre-determined) order of decoding; v) for each transmitter source, assuming perfect cancellation of signals of preceding transmitter sources; vi) computing a signal-to-interference-noise-ratio SINR responsive to

Abstract: Transmission is scheduled in a multi-cell multi-carrier wireless network. Assignments are determined for subcarriers by determining marginal gains for receivers, determining a receiver and an associated base station corresponding to a highest marginal gain, and assigning the receiver to the base station. These steps may be iteratively repeated until each of the receivers is assigned to a base station. The subcarriers are then allocated to the receivers by selecting the receiver with the highest gain. Alternatively, assignments are determined for subcarriers by determining a maximum additional queue size reduction, determining an assignment for each of the subcarriers, determining a receiver associated with a base station that has the determined maximum additional queue size reduction, assigning the receiver to the base station, and allocating the subcarriers to the receivers in the base stations.

Abstract: A method includes the steps of i) listing out all possibilities for a first symbol of a two stream signal; ii) determining a second symbol of the two stream signal for each of the first symbol listed out, iii) evaluating a metric for each of the first symbol and second symbol pair, iv) listing out all possibilities for second symbol, v) determining a first symbol for each choice of the second symbol listed out, vi) evaluating a metric for each of the second symbol and first symbol pair, vii) determining an exact maximum log likelihood ratio for all bits using the metrics, and viii) decoding codeword(s) in the two stream signal using the determined exact maximum log likelihood ratio for all bits.

Abstract: Data is transmitted between a central office and customer premises by a wavelength division multiplex passive optical network. Two laser beams with separate wavelengths are transmitted from the central office to an optical network unit in the customer premises. Both laser beams carry downstream data. One laser beam is intensity modulated by on/off keying. The other laser beam is phase modulated by differential phase shift keying, which maintains a constant optical intensity. The first laser beam is received by a first optical receiver, which demodulates the first downstream data. The second laser beam is split in two. One laser beam is sent to a second optical receiver, which demodulates the second downstream data. The other laser beam is sent to a reflective semiconductor amplifier, which modulates the beam with upstream data and transmits the beam back to a receiver in the central optical system.

Abstract: Disclosed is a method and system for modeling invariant relationships between flow intensity measurements in a distributed system. In the method, a measurement is randomly selected from a plurality of flow intensity measurements. The method searched for relationships between the randomly selected measurement and each remaining one of the plurality of flow intensity measurements, and each of the flow intensity measurements having a relationship with the randomly selected measurement is grouped into a cluster with the randomly selected measurement. The method than determines relationships between all of the flow intensity measurements in the cluster. This method is repeated with the remaining flow intensity measurements until all of the flow intensity measurements are grouped into a cluster.

Abstract: Data is stored in a distributed data storage system comprising a plurality of disks. When a disk fails, system reliability is restored by executing a set of reconstructions according to a schedule. System reliability is characterized by a dynamic Normalcy Deviation Score. The schedule for executing the set of reconstructions is determined by a minimum intersection policy. A set of reconstructions is received and divided into a set of queues rank-ordered by redundancy level ranging from a lowest redundancy level to a highest redundancy level. For reconstructions in each queue, an intersection matrix is calculated. Diskscores for each disk are calculated. The schedule for the set of reconstructions is based at least in part on the intersection matrices, the Normal Deviation Scores, and the diskscores.

Abstract: A MMSE-based deterministic sequential Monte Carlo (SMC) method for MIMO demodulation exhibiting square root complexity in terms of constellation size. Further extensions to the method reduce the search space resulting in significant reduction in computational requirements while minimally impacting performance. As a hard decision algorithm, the methods achieve sphere decoder performance while imposing a much smaller computational load.

Abstract: A computer implemented method for modeling and verifying concurrent systems which uses Satisfiability-Modulo Theory (SMT)-based Bounded Model Checking (BMC) to detect violations of safety properties such as data races. A particularly distinguishing aspect of our inventive method is that we do not introduce wait-cycles in our symbolic models for the individual threads, which are typically required for considering an interleaved execution of the threads. These wait-cycles are detrimental to the performance of BMC. Instead, we first create independent models for the different threads, and add inter-model constraints lazily, incrementally, and on-the-fly during BMC unrolling to capture the sequential consistency and synchronization semantics. We show that our constraints provide a sound and complete modeling with respect to the considered semantics.

Abstract: An analog to digital converter (ADC) structure and method includes a photonic filter bank having at least two filters. The at least two filters are configured to create a corresponding spectral tributary from an input signal at a target rate, and the at least two filters are configured to exhibit orthogonality properties between respective tributaries. An optical/electrical (O/E) converter is coupled to each of the at least two filters in a respective spectral tributary to convert an optical input to an electrical output. An analog to digital converter (ADC) is coupled to each of the O/E converters in a respective spectral tributary to sample the electrical output at a fraction of a target rate and to convert a sampled analog electrical output into a digital signal. A synthesis filter is coupled to each of the ADCs in a respective spectral tributary to reconstruct the input signal digitally at the target rate.

Abstract: A method and system for improving spatial reuse in a wireless local area network (WLAN) by per-client dynamic power management. Each access point of the WLAN associates each of its clients with a minimum power level. A central controller of the WLAN generates a schedule for transmission at different power levels, and each access point varies its transmission power level based on the schedule. An access point transmits data packets, at the scheduled transmission power level, to clients associated with a minimum power level that is less than the scheduled power level.

Abstract: A method includes the steps of: i) listing out all possibilities for first symbol of a two stream signal; ii) determining a second symbol of the two stream signal for each said first symbol listed out, iii) evaluating a metric for each said first symbol and second symbol pair, iv) determining the exact maximum log likelihood ratio for all bits associated with said first symbol using said metrics, v) decoding a codeword-1 using the maximum log likelihood ratios, vi) re-encoding said codeword-1, vii) modulating said re-encoded codeword-1, viii) subtracting said modulated re-encoded codeword-1 from said two stream signal, ix) determining metrics for all possibilities for second symbol in the signal obtained in viii, x) determining the maximum log likelihood ratios for all bits associated with second symbol, and xi) decoding said codeword-2 using the maximum log likelihood ratios for all bits associated with said second symbol.

Abstract: The present invention is directed to improving utilization in a peer-to-peer network. Each node in a peer-to-peer network is assigned a number of preferably fixed-size storage slots proportional to the node storage, a first portion of which is allocated to storage zones and a second portion of which is allocated as a free slot reserve. In accordance with an embodiment of an aspect of the invention, this split of a storage zone is delayed until the storage zone becomes full, referred to herein as “lazy splitting”. In accordance with an embodiment of another aspect of the invention, it is advantageous to allocate more storage slots at a node than its actual physical capacity referred to herein as “oversubscription”. In accordance with an embodiment of another aspect of the invention, each physical node is allocated at least one storage zone, even as a new node is added to the system.