Abstract: A novel and useful method of creating signatures for use in classifying failures of software programs in general and circuit design simulation tests in particular. Upon failure of a processor simulation test, the method of the present invention creates a signature comprising the sequence of source code commands executed shortly before the failure. The created signature, along with the reported error message together provides a functional grouping of the tests into groups of similar failures. After executing a suite of processor simulation test programs the resulting signatures are classified by their respective error messages and signatures. The results are then analyzed to pinpoint any program errors, or (in the case of processor design tests) design flaws causing the simulation test failures.

Abstract: A feedback mechanism to reduce current variation observed in a current reference branch circuit by using body voltage control to compensate process, temperature and supply voltage variations. The current reference output voltage, which is proportional to the reference current, is sampled into a feedback loop, which controls the field effect transistor body voltage. The method and mechanism uses Corner Robust Current Reference in order to keep the design simple and diminish variation between Process Voltage Temperature (PVT) corners. This method exhibits small variation in the reference current magnitude.

Abstract: A novel and useful method of constructing a fast approximation of a dynamic Huffman table from a data sample comprising a subset of data to be compressed. The frequency of incidence of each symbol in the sample is calculated, and the symbols are then allocated to predefined bins based on their frequency of incidence. The bins are then transformed into binary sub-trees, where the leaf nodes of the binary sub-trees comprise the symbols of the bin associated with the binary sub-trees. The binary sub-trees are then combined via nesting, thereby creating a coarse grained binary tree, where all leaves are mapped to a specified number of depths. The coarse grained binary tree is then traversed, thereby yielding a canonical code for each symbol, thereby defining the entries for a dynamic Huffman table.

Abstract: A real-time optimizing information transfer and interrupt event scheduling scheme for a communications transceiver incorporating multiple processing elements. The scheme is particularly applicable for use in UMTS based communications transceivers, i.e. W-CDMA transceivers adapted for User Equipment (UE). The interrupt scheduling scheme of the present invention is operative to perform the scheduling of interrupts used to configure a data transfer device to effect the timely transfer of data from a hardware based chip rate processor to a memory buffer for subsequent processing by software running on a DSP or other processor platform.

Abstract: A clock reconstruction mechanism for synchronous TDM communications traffic transported over asynchronous networks such as Ethernet networks. The invention is applicable to edge switches in Metropolitan Area Networks (MANs) that transport legacy TDM traffic using a Circuit Emulation Services (CES) module whereby TDM traffic is encapsulated and transported across the Ethernet network where it is de-encapsulated and clocked out to the destination. The mechanism encapsulates the input TDM data stream into Ethernet packets and inserts a network timestamp within the packet. At the destination CES, a local timestamp is generated for each received packet as it is received. The network timestamp is extracted and input along with the local timestamp to a Digital Time Locked Loop (DTLL) which is operative to accurately reconstruct the original transmit TDM clock.

Abstract: An image publishing system provides a distribution mechanism whereby images are forwarded automatically to users in accordance with a set of publication rules. The rules determine which images are to be sent to which users. The images are forwarded to users as they become available on an image archive storage device. This overcomes the requirement of users having to manually request the transmission of each individual image they would like to view. Progressive image streaming techniques employing compression are used to transmit images in encoded layers of increasing accuracy and quality. Means is also provided permitting users to view any image queued for transmission at a publication server, regardless of how much of the image has been received by a client computer. This allows images whose data transmission has not even begun yet to be viewed by a user. A user interrupts the normal background process at any time and requests to view a particular image.

Abstract: A sealed dispensing apparatus suitable for packaging and dispensing a single service portion of a food product. The food product is contained within an inner container cavity formed by an outer cover and a center member. Draw means are provided for transferring a force from the user to the outer cover, whereby the force peels the outer cover from the center section, thus folding the outer cover over itself as it is removed from the center section. The food product is dispensed when the inner container is opened by removing the outer cover from the center member. An optional outer container seals and holds portions of bread or other sandwich portions while the inner container is located therebetween. Box means holds the combination formed by the inner container and the outer container as well as optional condiments.

Abstract: An end-to-end monitoring mechanism whereby edge nodes are notified that a particular path flows through a local protection tunnel along the way. The notification mechanism utilizes OAM packets which include a link protection indication that are transmitted on the Ethernet service layer. The link protection indication may be represented by one or more flags to indicate that local protection is in place along the path. The mechanism enables fast local protection to be used with slower end-to-end protection by informing the latter when local protection is activated. In an implementation in which local-protection does not preserve the CIR of the protected traffic, the invention provides minimal interruption of Committed Information Rate (CIR) connections by minimizing the time traffic is diverted through local protection tunnels. Notification of the edge node that local protection is in use occurs very quickly, thus allowing the edge node to rapidly switch to a backup path.

Abstract: A link based network protection path calculation mechanism wherein a protection route is calculated that is guaranteed not to traverse the link it is intended to protect. The mechanism takes advantage of the fact that the same color cannot pass twice through the same optical fiber. The protection path is determined by eliminating all colors from the logical topology of the network except for the color corresponding to the link to be protected before executing the search algorithm. This serves to guarantee that the protection path calculated will not traverse the same physical fiber as the link to be protected. Virtual colors can be assigned to the links running through fiber bundles such that they do not pass through the same fiber/bundle twice.

Abstract: A novel and useful virtual private network (VPN) mechanism and related security association processor for maintaining the necessary security related parameters to perform security functions such as encryption, decryption and authentication. A security association database (SAD) and related circuitry is adapted to provide the necessary parameters to implement the IPSec group of security specifications for encryption/decryption and authentication. Each security association (SA) entry in the database comprises all the parameters that are necessary to receive and transmit VPN packets according to the IPSec specification.

Abstract: An optical network terminator for terminating and reducing the accumulated noise in optical networks, particularly ring based networks. The terminator eliminates problems of noise accumulation from amplifier spontaneous emission (ASE), thermal noise, etc., while providing bi-directional communications in the optical network. The optical network may have any topology including ring, star, mesh, point-to-point, etc. In the case of an optical ring, the ring is broken and an optical terminator is placed in line therewith. The optical network terminator includes a filer such as an optical demultiplexer/multiplexer or Fiber Bragg Grating (FBG) based filter. Each individual wavelength of light is filtered and a multi-wavelength optical output is generated whereby the noise accumulation is removed. Each channel is adapted to only pass a band-limited signal around the center frequency corresponding to the wavelengths supported by the particular optical ring network.

Abstract: A fast protection mechanism capable of maintaining end-to-end and fast local protection on the order of sub 50 ms for both VLAN only based connections and for connections that are based partially on VLAN technology and partially on MPLS technology. The present invention is suitable for use edge switches configured in a stack or ring topology. The NMS provisions both the main and alternative VLANs in each edge switch in the stack portions of the network. When a link failure occurs, the edge switches on either end of the failed link immediately switch all protected traffic going through that link to the alternative VLAN. The packets are then returned on the links over which they were received. Hello messages are used to signal the remote end that a link failure has occurred and that protected traffic must be switched to the main or alternative VLAN in accordance with the VLAN the Hello message was received on.

Abstract: A 1:N protection scheme that provides both equipment and line protection against a single point of failure for a network hub situated in an optical ring network. The invention is suitable for use in DWDM based optical ring networks, and in particular, in networks constructed having a logical star over physical ring topology. The hub is modified to comprise N+1 transceivers, assuming an N channel DWDM network wherein each of the N transmitters operates using a different wavelength. Protection against line failures is achieved by optically splitting the transmit signal into two paths and transmitting each separately in opposite directions over the ring (i.e. 1+1 protection). In the event of a line failure, the other signal should still arrive at the destination. Protection against equipment failures is achieved through the use of a spare transceiver having a tunable wavelength of operation (i.e. 1:N protection).

Abstract: A novel and useful apparatus for and method of determining the channel order and channel estimate in a communications system. The present invention is suitable for use with a wide range of channels and is particularly useful in estimating wireless channels such as GSM and other types of cellular channels. A channel estimate is performed on the entire received training sequence. Those taps having an energy larger than the energy of a channel estimation error quantity are selected for the final channel estimation model. The estimation error is calculated by dividing the complete received training sequence into two different portions, wherein both portions are of equal size. A channel estimate is used to calculate the channel estimate of both portions which are then used to calculate the channel estimation error quantity.

Abstract: A method and apparatus for estimating channel tap delays of multipath components in a CDMA received signal. The search for the tap delays are split into two phases namely, a phase 1 and a phase 2 search. The phase 1 search is a coarse resolution quick search adapted to generate a rough estimate of the location of the tap delays. During this phase, the candidate codes are summed and the input signal correlated with the code sum creating an ambiguity in the code associated with the multipath. A finer resolution slower phase 2 search resolves the code ambiguity present in the initial rough estimates of the phase 1 search. Additional phase 2 correlations may be performed to implement a code-tracking loop.

Abstract: A novel and useful channel tracking mechanism operative to generate channel estimate updates on blocks of samples during reception of a message. The tracking mechanism is based on the weighted recursive least squares algorithm and implements the estimation process by recursively updating channel model parameters upon the arrival of new sample data. The mechanism is operative to update channel estimate information once per sample block. An interblock exponential weighting factor is also applied. The block length is chosen short enough to enable good tracking performance while being sufficiently long enough to minimize the overhead of generating preliminary decisions and of updating precalculated tables in the equalizer. The method of the invention can be performed in either hardware or software. A computer comprising a processor, memory, etc. is operative to execute software adapted to perform the channel tracking method of the present invention.

Abstract: A reduced complexity correlator that enables the re-use of the most complex portions of a correlator, namely the multiplier and adder. The correlator of the present invention is especially well-suited for use in CDMA and W-CDMA spread spectrum communication systems that require the use of numerous correlators in their operation. Multiple input samples, multiple codes and integration results are stored in shift registers and circularly shifted and clocked out at appropriate clock rates such that the multiplication and accumulation steps of the correlation process are synchronized.

Abstract: A lossless image streaming system for the transmission of images over a communication network. The system eliminates the necessity to store a compressed version of the original image, by losslessly streaming ROI data using the original stored image. The imaging system also avoids the computationally intensive task of compression of the full image. When a user wishes to interact with a remote image, the imaging client generates and sends a ROI request list to the imaging server. The request list can be ordered according to the particular progressive mode selected (e.g., progressive by quality, resolution or spatial order). The imaging server performs a fast preprocessing step in near real time after which it can respond to any ROI requests in near real time. When a ROI request arrives at the server, a sophisticated progressive image encoding algorithm is performed, but not for the full image. Instead, the encoding algorithm is performed only for the ROI.

Abstract: A novel and useful apparatus for and method of I/Q gain mismatch compensation for use in a communications receiver. The invention is operative to calculate an estimate of the I/Q gain mismatch. Each input sample is subsequently multiplied by the inverse of the estimate to generate compensated samples. The training sequence portion of the uncompensated input samples is used to generate the I/Q gain mismatch estimate. In accordance with the present invention, the H matrix used in calculating the gain mismatch estimate is pre-calculated for several channel lengths and stored in memory. An estimate of the channel is generated which provides the channel length and the location in the input sample buffer of the first training sequence sample to be used in calculating the gain mismatch estimate. The channel length is used to determine the number of training sequence samples to be used and to select one of the previously calculated H matrices.

Abstract: A bidirectional direct sequence spread spectrum half-duplex RF modem that can be applied to transmit and receive numerous types of analog and digital pulse modulation. The modem incorporates a SAW based correlator for performing the spreading and de-spreading functions in the transmitter and receiver. A SAW resonator fabricated on the same monolithic substrate provides the frequency source for the oscillator. An upconverter/downconverter provides frequency translation to the desired frequency band. Pulse gating and interrogating pulse shaping are employed to reduce the spectral side bands of the transmitted spread pulse. The RF modem operates as an analog or digital pulse transmitter and receiver. It is adapted to be generic and is versatile enough to be used in many different types of data communication systems, such as OOK, PWM and PPM. The RF modem can be used as the physical (PHY) layer in a layered communication system such as the ISO OSI communication stack.