Abstract: The present invention provides a method and an apparatus for detecting at least one repeater between a base station and a mobile unit. The method includes determining a first estimate of a distance traveled by a signal on a wireless communication link between the base station and the mobile unit, determining a second estimate of the distance traveled by the signal on the wireless communication link between the base station and the mobile unit, and comparing the first and second estimates. The method also includes determining whether the signal was processed by the at least one repeater based upon comparing the first and second estimates.

Abstract: An antenna array includes four closely spaced, linearly arranged antenna columns. At least two of the columns, e.g., the center two columns, are dual-polarized. Spacing between neighboring columns is about ½?, where ? is the free space wavelength at the network carrier frequency. Each column includes a first vertical linear array of radiating elements or groups of elements (sub-arrays) connected to a port. The dual-polarized columns each further include a second linear array of radiating elements oriented at a different polarization than the first array. (For example, horizontal/vertical or slant 45°.) Array ports are connected with four RF feed cables using duplexers in such a way so as to provide two different antenna configurations for forward link and reverse link frequencies, namely, a four-column closely spaced beam-forming array at the forward link and a two-column dual-polarized array at the reverse link for 4-branch diversity reception.

Abstract: The present invention provides an optical beamforming RF transmitter. In one embodiment, the optical beamforming RF transmitter includes an optical WDM splitter having an input and a plurality of outputs. The optical beamforming RF transmitter also includes an array of antennas, where each antenna has an optical input configured to drive the corresponding antenna, and an array of optical modulators, such that each modulator has an output connected to a corresponding one of the antennas and an input connected to one of the outputs of the optical WDM splitter. The optical beamforming RF transmitter further includes a mode-locked laser having an output optically coupled to the input of the optical WDM splitter.

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: 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: 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: 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 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: 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: 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: 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 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: A monolithically integrated tunable wavelength converter and variable optical delay device(s) that is capable of providing optical delay(s) of any length. Advantageously, our devices are both compact and readily realized as a photonic integrated circuit (PIC) on a semiconductor substrate.

Abstract: A data-aided, multi-symbol phase estimation (MSPE) scheme is described for improving receiver sensitivity in the direct-detection of optical differential multi-level phase-shift keying (ODmPSK) signals including optical differential quadrature phase-shift keying (ODQPSK) signals, ODQPSK signals with amplitude shift keying (ODQPSK+ASK), optical differential 8-level phase-shift keying (OD8PSK) signals with eight phase levels, and optical differential phase-shift keying signals with more than eight phase levels. The use of data-aided MSPE substantially reduces the “differential detection penalty,” with receiver sensitivity approaching that of coherent detection schemes.

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 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: 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 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.