Abstract: A colorless tunable optical dispersion compensator (TODC) comprising a silica arrayed-waveguide grating (AWG) directly coupled to a polymer thermo-optic lens. As a result of its inventive construction, the device exhibits low loss, large tuning range, low electrical consumption and is readily manufactured using standard processes. Additionally, the TODC is fully solid-state and scales to a large figure-of-merit (dispersion range times bandwidth squared).

Abstract: An optical transmitter includes a modulator, a dispersion adjustment module, and an optical amplifier. The optical transmitter is configured to transmit optical pulses over a free-space optical communication channel. The modulator is configured to produce an optical carrier that is amplitude and/or phase modulated by data. The dispersion adjustment module is connected between the modulator and the amplifier and is configured to substantially change temporal widths of optical pulses received from the modulator by changing dispersions of the received optical pulses.

Abstract: A frequency offset estimator is employed that estimates the frequency offset in signal frames that include only binary Phase-Shift Keying (BPSK) carriers in OFDM systems. Specifically, the offset frequency estimator takes advantage of those OFDM systems in which some OFDM symbols only have carriers with either zero or the BPSK constellations. In many WLAN systems such as the system described in standard IEEE802.11a, transmission frames include only BPSK symbols, which are used for training and other services. By making use of these BPSK symbols in each frame, a very accurate estimate of frequency offset can be obtained. By advantageously employing the frequency offset estimator of this invention, a carrier recovery system can achieve high performance even under strong ISI and low SNR. In a specific embodiment of the invention, BPSK carriers spread to be on a line in a complex plane at an angle to the real axis.

Abstract: The system includes a jitter buffer for receiving speech packets in a Voice over Internet Protocol (VoIP) system, a playback device for adjusting the playback speed of the received speed packets, and a jitter buffer manager for detecting out of sequence packets in the jitter buffer and for sending commands to the playback device to adjust playback speed based on the detection. The speech signal is played back at the nominal speed when there are no out of sequence packets. The playback speed is decreased when an out of sequence packet is detected, thereby tending to increase the jitter buffer length. When an out of sequence packet arrives, the playback speed is increased in order to restore jitter buffer length to its nominal length.

Abstract: In the absence of a continuous channel from the mobile terminal that incorporates a CRC in each transmitted frame from which the base station can derive a power control signal for feedback to the mobile station for maintaining the mobile station's pilot Eb/N0 level at a desired target that corresponds to a particular frame error rate, the pilot signal received by the base station from the mobile terminal itself is arranged in a frame format. Each pilot frame is compared with an a prioi known transmitted pilot signal bit pattern to determine whether it has been received in error. In response to a comparison of a received pilot frame with the expected known bit pattern of the pilot frame, an error signal is derived, which in the described embodiment is either a step-up or step-down signal that is fed back to the mobile terminal to increase or decrease its transmitted pilot Eb/N0 level, respectively.

Abstract: In a telecommunications system (100), a method and apparatus for buffering the initial speech of an initial speaker in a push-to-talk call is disclosed. The method includes the steps of determining at least one participant or group to call (410, 510), sending a call request to the at least one participant or group (520), determining if the at least one participant or group is registered with the telecommunications system, notifying the initial speaker to begin speaking after determining at least one participant is registered with the telecommunications system but prior to connecting all called parties, receiving and digitizing voice packets from the initial speaker, storing the digitized data packets in a storage medium and transmitting the digitized voice packets when a predetermined packet transmission triggering event occurs.

Abstract: The present invention provides a system for, and method of, adaptable testing of backplane interconnections. In one embodiment, the system includes a board detector configured to determine a relative arrangement of a plurality of hardware boards populating positions associated with the backplane interconnections. Additionally, the system also includes a test coordinator coupled to the board detector and configured to adaptively backplane test at least a pair of the plurality of hardware boards based on the relative arrangement.

Abstract: A hybrid telecommunications switch includes synchronous transfer mode (circuit), and packet switch fabrics. A controller within the hybrid switch determines the type of traffic that is to be switched in either switch fabric. Real time traffic, such as voice traffic, may be routed by the controller to an circuit switch fabric for example. Internet protocol (IP) and packet traffic may also be routed to the circuit switch fabric. A SONET/SDH overhead byte associated with traffic may be employed by the controller to determine which switch fabric to employ. Circuit switch resources are provisioned for circuit, IP and packet traffic. IP or packet traffic, as indicated by the path overhead byte, is routed to the packet switch after resources are dynamically allocated for the traffic.

Abstract: The delay setting of an optical delay line interferometer (DLI) used to decode differentially encoded phase shift keyed signals (DPSK or DQPSK) is controlled using a control signal representative of the ratio Perr2/Perr1 of the rate of occurrence of double errors and the rate of occurrence of errors. The ratio Perr2/Perr1, as the delay setting of the DLI is varied, exhibits a characteristic W-shaped structure consisting of a local maximum at the optimum value and two minima adjacent to the maximum, one on each side of it. This structure is present over a wide range of signal to noise ratio and residual dispersion.

Abstract: An embedded echo canceller in a wireless network is tested by routing traffic signals through the echo canceller and measuring input and output signals of the echo canceller as it operates to remove echo signals from the traffic signals. To test the operation of the echo canceller in regards to a plurality of hybrid circuits, a hybrid interface box controlled by an echo canceller test program is attached to an upstream end of the echo canceller. An ISUP communication is established between two wireless units, through the echo canceller and a loop around trunk. The communication is traced, and a traffic channel portion of the communication (separate from a signaling channel) is broken. Because the two channels are separate under ISUP, this does not terminate the communication. The hybrid interface box is controlled to inject test signals into the traffic channel, and the operation of the echo canceller is measured.

Abstract: A network operating system NOS for an agile optical network with a plurality of mesh interconnected switching nodes, manages the network using an object-oriented network information model. The model is common to all applications requiring the data stored in the network managed information base. The core model can be expanded for serving specific application areas. The NOS is organized in layers, at the optical module level, connection level and network level. A distributed topology server DTS organizes the physical, logical and topological data defining all network entities as managed objects MO and topology objects TO for constructing a complete network view. The network information model associates a network element NE information model, specified by managed objects MO and a topological information model, specified by topology objects TO.

Abstract: The invention includes an apparatus for modulating an optical signal. The apparatus includes a modulating mechanism comprising a plurality of modulating component arrays, each modulating component array comprising a plurality of modulating components, wherein adjacent ones of the plurality of modulating components in each modulating component array are separated by gaps, and wherein adjacent ones of the plurality of modulating component arrays are offset along a dispersion direction of an incident optical signal such that the gaps associated with the adjacent ones of the plurality of modulating component arrays are offset. In one embodiment, rows of the modulating components in the modulating component arrays are offset along the dispersion direction of the incident optical signal by a fraction of the modulating component pitch.

Abstract: Capacity design of an optical network for demands of fast path restorable (FPR) connections forms a linear programming sizing problem for a optimal routing. A dual of the linear programming sizing problem is formed and solved with an approximation algorithm. Edge lengths are initialized based on i) the inverse of the edge's capacity and ii) a scalar constant. Then, the approximation algorithm proceeds in phases to route each commodity over the edges of a graph. During each phase, the demand's flow is sent from the source to destination via multiple iterations. During each iteration, the set of shortest disjoint paths from the source to the destination is determined, a portion of the flow is sent, and the lengths of the edges that carry the flow are updated. The value employed to scale the network is generated after the last phase from the maximum ratio of edge flow to edge capacity.

Abstract: A method for the automatic provisioning of a network element (NE) includes receiving a client signal at a tunable optical translator (OT) in the NE, determining the set of channels supported by the OT that are able to correspond to the client signal, eliminating the channels that have connections, that may be present on a line side of the NE in a laser off scan process, or that have not been equipped or otherwise provisioned for transmission, tuning the OT to each of the remaining channels and determining the optical power level of each channel on a line side of the NE in a laser on scan process. Subsequently, the channel with the highest power level is selected to transmit the client signal and associations for a point to point connection for that channel are added for that OT to a database of associations for the NE.

Abstract: Resources within a hybrid packet-circuit network are dynamically reallocated based on demand. In response to an edge switch requesting additional first resources, a network manager evaluates a plurality of possible communication paths and potential network changes to determine an optimum configuration for providing the additional first resources. Network switches are instructed by the network manager to reallocate second resources such as packet-switched resources to first resources such as circuit-switched resources.

Abstract: A method for locating a mobile device in a wireless communications system comprised of a plurality of base stations is provided. The method comprises associating the mobile device with a first base station of the plurality of base stations. Thereafter, a paging signal is delivered from a subset of base stations associated with the first base station to the mobile device. The subset of base stations may correspond to a network active set of base stations associated with the mobile device. Thereafter, when a signal from one of the base stations in the subset of base stations is received, indicating that the mobile device responded to the paging signal from the one base station, then the mobile device is located and may be associated with the one base station for future paging attempts.

Abstract: Data is distributed over multiple connections through a network in successive groups of containers such that respective containers of each group are transmitted via respective ones of the connections. Each container contains an identifier of the group to which the container belongs. The output of the network data from containers that have been received is buffered to compensate differences in the delays of transport via different connections. An oldest identifier value received via the connections during a time frame is detected by determining a plurality of respective minimum values of the identifiers received in the time frame. Each minimum value is determined among received identifiers from a respective sub-range of possible identifier values. A “sequentially first” sub-range of successive sub-ranges, for which at least one of the minimum values has been determined, is then determined. The minimum value of the “sequentially first” sub-range is then selected as the oldest identifier.

Abstract: A method and apparatus for network routing in packet-based networks which advantageously takes traffic conditions into account dynamically in determining the “best route” for routing a packet to its intended destination. Illustratively, a potential function is employed whereby hypothetical electrostatic potential values are calculated at each node or link of a network, and the packets are routed in accordance with these potential function values (e.g., in the direction of the lowest neighboring value). The potential function values may be advantageously calculated based on queue lengths at the various nodes (or links) in combination with a minimum-cost distance calculated to the packet's intended destination.

Abstract: In a method of tracking a user in a communication network supporting a broadcast-multicast service, the network classifies groups of users into tracking areas. Movement of a user may be tracked as the user crosses a boundary between two tracking areas in the network. The method may enable a balance to be achieved between use of uplink overhead and the level or granularity of tracking desired, so as to conserve radio resources.

Abstract: A system is implemented on a wireless network for adjusting a forward link power control parameter based on forward link feedback. A wireless unit is in communication with several base stations during soft handoff, and provides feedback relating to forward link quality, e.g., forward link pilot signal strength or traffic channel frame error rate. The feedback is compared to a comparison or reference point (such as target frame error rate, or a maximum pilot signal strength in the active set) chosen for gauging the quality or nature of the feedback for power control purposes. Based on this comparison, a power control parameter of one or more of the base stations may be adjusted upwards or downward. The power control parameter may be a forward link reference transmit power level “Pref” used to control base station power transmission levels in the presence of power control bit errors.