Abstract: ISDN access to a telecommunications network is provided to customers at different locations by sharing a D-channel controllers (DCC's) positioned within the network in close proximity to the ISDN-capable toll switches serving those customers. The customers provide call set up parameters to a DCC via a user interface system (UIS) at the customers premises that communicates via a dial-up data connection with a respective user support system (USS) connected to the DCC. The DCC in turn formulates ISDN signaling messages that are sent to the switch via a PRI interface and set up an appropriate communications path through the network to a desired destination. Data originating in customer premises equipment is received in the switch via a T1 access line operating in the "non-facility associated signalling" mode.

Abstract: Intelligent network telephone calls are processed by an intelligent terminal which cooperates with network elements such as a database that contains information with respect to such calls. When a call requiring intelligent network treatment is first made from an intelligent terminal, if the terminal does not have the requisite information to complete the call, the call is processed by network elements such as an originating switch and a network database which attempt to find routing information for the call. However, if the call contains an indication that (a) the calling party requests a down load, and the database record associated with the dialed number indicates that routing information stored in the database is marked for down loading, then the routing information is down loaded and stored in the intelligent terminal.

Abstract: A super-rate signal is split (213) by an inverse multiplexer (200) into plural SONET STS-1 signals for transmission over separate facilities. At the receiver (500) the plural received signals are likely to have misaligned frames and payloads within the frames. In order to realign the plural signals so that they can be properly recombined to reform the original super-rate signals, the SONET A1 and A2 framing bytes together with the H1 and H2 pointer bytes are extracted (506) and used to determine (507) from where in plural buffers (508) stored frames of each received signal should be read out so that the read out signals are properly aligned. If misalignment of greater than one frame is to be corrected, plural frames of each received signal are stored and the SONET J1 byte is used in conjunction with the framing and pointer bytes to properly align the signals.

Abstract: Acousto-optic polarization converters can be used as the primary optical components in a multi-channel wavelength-routing switch (101). Switching efficiency is decreased and the polarization converted wavelength channels are shifted towards each other, however, when closely neighboring channels are selected simultaneously. This degradation has serious consequences for many applications of the acousto-optic polarization converter. By applying counterpropagating acoustic waves from opposite ends of a converter (400) and using an acoustic absorber (417) to separate the left and right sides of the converter at a defined coupler crossover length, L.sub.x, this deleterious degradation is substantially reduced.

Abstract: A passband-flattened acousto-optic polarization converter (100) in which two acoustic waveguides (14, 20) are formed in a substrate and a separated by a small gap (18) such that the two acoustic waveguides act as a directional coupler in which acoustic power is transferred back and forth. An interdigitated transducer (12) launches a surface acoustic wave in the first acoustic waveguide, and an optical waveguide is formed in the middle of the second waveguide. A partial acoustic absorber (27) is formed over both acoustic waveguides at a crossover length at a distance from the transducer equal to the point at which the acoustic wave has transferred from the first to the second waveguides and back again. The partial absorber absorbs most of the acoustic amplitude with the attenuated acoustic amplitude being coupled back again to the second acoustic waveguide but at an opposite sign.

Abstract: In digital transmission, the combination of transmitted pulse shape and receiver sampling time that maximizes the magnitude of the channel output pulse sample is determined. The transmitted pulse shape is represented as a linear combination of orthonormal functions. The coefficients that multiply each of the functions are determined by measuring at the receiver and transmitting back to the transmitter the response of the channel to each independently transmitted function at an approximation to the optimal sampling time. A pulse shape is formed using the calculated coefficients and is transmitted to the receiver where the timing of its maximum is determined, which represents a next approximation to the optimal sampling time.

Abstract: A variable-length codeword encoder is disclosed which produces 8-bit output segments for storage in a buffer (23) for subsequent transmission over a transmission channel (24). The encoder includes two memory tables (15, 16), which produce in response to each input symbol to be encoded, a variable-length codeword and an a codeword length. An accumulator (31, 33) accumulates, modulo-8, the successive codeword lengths, producing a carry signal during any clock cycle in which eight or more bits codeword bits are accumulated. At each clock cycle, the variable-length codeword is input to the parallel inputs of a cross bar shift control circuit (30). This shift control circuit produces a 16-bit output in which the input word is embedded.

Abstract: In a TDM/TDMA portable radio communications system, the modulated RF signal transmitted by a portable handset unit is amplified for uplink transmission to a port by an adaptive class AB power amplifier. A class AB amplifier provides the necessary amplification for the low power levels to be output by the portable units, but must be biased just slightly "on" with no signal input for required maximum efficiency and linearity. In order to maintain the amplifier at a proper bias level over changing temperature conditions and free from the effects of device aging and device-to-device variations, the drain current of the amplifier is monitored each frame outside the burst interval in which the portable is transmitting and thus when no signal is present at its input. The drain current is then controlled by adjusting the gate voltage to compensate for any variations.

Abstract: A system for spectrum sharing between a point-to-point microwave system and a TDM/TDMA wireless communications system in a common geographical area is described. Each transmitter/receiver in the point-to-point microwave system transmits, in addition to its normal information signal, a beacon signal which is uniquely associated with the receiver receive frequency. In selecting uplink and downlink frequencies for port assignment, each port monitors the beacon frequencies and selects as uplink and downlink frequencies, frequencies which associated beacons fall below a predetermined threshold. Similarly, before accessing the wireless communications system through a selected port, a portable monitors the beacons associated with the selected port's uplink frequency. If the beacon associated with the uplink frequency exceeds a threshold, the portable selects an alternate port through which to access the network.

Abstract: In a multiwavelength lightwave communications system automatic self-power regulation on a channel-by-channel basis is achieved with a cascade of multiwavelength amplifier modules (200), wherein each multiwavelength amplifier module in the cascade includes a plurality of pump-shared parallel fiber amplifiers (208) operated in gain-saturation and connected between an optical demultiplexer (203) and multiplexer (209). An optional first gain stage (202) improves performance with higher optical signal-to-noise ratio. By self-regulating the power in each channel, the communications system is scalable, allowing the system to grow without deleterious effects due to power spread.

Abstract: In a TDM/TDMA digital radio communications system a few selected ports are connected to a fixed common timing reference and designated as master ports. Each master port is assigned a hierarchical value of zero. Every other port is initialized a high hierarchical value before performing an autonomous iterative procedure to synchronize timing to its nearest master port. By demodulating downlink signals transmitted from other ports when its own transmitter is turned off, a receiving port selects only a fixed number of ports providing the best signal quality with respect to which to adjust its timing. The relative timings and the hierarchical values of the transmitting ports are compared with those of the receiving port. If the hierarchical value of the receiving port, H.sub.R, is greater than or equal to the lowest hierarchical value, H.sub.L, of the transmitting ports, it adjusts its timing based on the timing differences with respect to the set of ports having a hierarchical value of H.sub.

Abstract: In a TDM/TDMA digital radio communications system, time synchronization between fixed ports is achieved by adjusting the timing of a first port in response to the average timing difference between the timing of that first port and the timing measured by that first port of the downlink signals transmitted by a fixed number of the other ports in the system, which downlink signals are detected at the first port and determined to have the highest signal quality measures. Each of the other ports in the system sequentially performs the same process and the entire process is then reiterated a plurality of times at all of the ports until timing of the system converges.

Abstract: A system for spectrum sharing between a point-to-point microwave system and a TDM/TDMA wireless communications system in a common geographical area is described. Each transmitter/receiver in the point-to-point microwave system transmits, in addition to its normal information signal, a beacon signal which is uniquely associated with the receiver receive frequency. In selecting uplink and downlink frequencies for port assignment, each port monitors the beacon frequencies and selects as uplink and downlink frequencies, frequencies which associated beacons fall below a predetermined threshold. Similarly, before accessing the wireless communications system through a selected port, a portable monitors the beacons associated with the selected port's uplink frequency. If the beacon associated with the uplink frequency exceeds a threshold, the portable selects an alternate port through which to access the network.

Abstract: A method for transmitting a packet via a sequence of nodes in a network is disclosed. The transmitted-packet contains a sequence of one or more identifiers in a sequence of fields 410, 420, 430, 440, 450, 460, 470, 480 and a pointer pointing to a particular identifier in the sequence of identifiers in a field 485 of a routing section of a header in the packet. A node of the sequence of nodes at which the packet is located selects a forwarding table from a set of forwarding tables maintained in a memory at that node. The node then retrieves an entry from the selected forwarding table indexed by the identifier in the sequence of identifiers pointed to by the pointer. The node then transmits the packet to the next node of the sequence of nodes indicated by the retrieved forwarding table entry.

Abstract: In a multiwavelength lightwave communications system channel-by-channel power regulation is achieved with a cascade of inhomogeneously broadened saturated fiber amplifiers spaced along the optical fiber transmission path. In the described embodiment, inhomogeneous broadening is achieved by immersing each of the erbiumdoped fiber amplifiers in the cascade in a bath of liquid nitrogen, thereby cooling each amplifier to approximately 77 K.

Abstract: In a TDM/TDMA portable radio communications system the uplink power transmitted by the transmitter of a portable unit to a fixed port is dynamically controlled by monitoring three measures in each uplink burst received by the port. These measures are a received signal strength indicator (RSSI), a quality measure (QM), and a word error indicator (WEI). The WEI is used to adjust an RSSI threshold upward and downward. If the QM is below a predetermined QM threshold or the RSSI is below the current value of the adjustable RSSI threshold, then additional uplink power is required, unless the RSSI is greater than a predetermined maximum RSSI value. If additional power is required a power control bit (PC), included within each downlink burst transmitted to the portable, is set to ONE and the portable, in response thereto, increases its output transmitter power.

Abstract: A distributed and adaptive method and system are provided for correcting routing errors due to packet deflections in a dual-shuffle exchange network (DSN). The DSN includes a shuffle-exchange network (SN) and an unshuffle-exchange network (USN). A packet that cannot be routed correctly will be temporarily "deflected" to a wrong route. This deflection, or routing error, is then registered and encoded in a routing tag of the header of the packet. Using this information, an error-correcting routing algorithm is then used to correct the error at a different part of the network. The method and system can be used either as the basis of a switch architecture of a ultra high-speed local-area network or metropolitan area network. Also, the method and system can be used in circuit switching. The DSN can achieve the Shannon's lower bound N log N on switch complexity with arbitrarily small packet-loss probability.

Abstract: An electrooptical device, such as a semiconductor laser, and an optical fiber are packaged together in light coupling alignment using an electrolytic technique that avoids heat-induced stresses that commonly result from joining methods that employ welding, soldering, or catalytic adhesive compositions. The particular technique of this invention also avoids the need to encapsulate the electrooptical device within an index matching gel to protect it from the electrolytic plating solution thereby enabling optical devices such as lenses, isolators, filters, etc, to be incorporated in the package. The electrooptical device is mounted onto a common metallic base and the optical device is mounted within the bore of a tubular metallic support member. This support member is affixed to the base by means of nodes of a flexible conductive gel and is positioned relative to the electrooptical device for maximum light coupling between the device and the optical fiber within the support member.

Abstract: Apparatus and method for large scale asynchronous transfer mode (ATM) switching utilizing tunable lasers and fixed-tuned receivers are provided. The apparatus, an optical switch, includes a plurality of input modules for receiving ATM cells to be switched and a plurality of output modules for outputting the switched ATM cells. The optical switch also includes an optical transmission network for optically transmitting each ATM cell from an input module to a particular output module, and a contention resolution device in electrical communication with the plurality of input modules for selecting the ATM cells from the plurality of input modules to be switched. Preferably, each output module includes a plurality of fixed-tuned receivers and each input module includes a plurality of tunable lasers. The fixed-tuned receivers of each output module are tuned to a particular wavelength so as to pass only those ATM cells optically received from the optical transmission network at the particular wavelength.

Abstract: The disclosed adaptive finite impulse response (FIR) digital filter architecture computes tap coefficient updates in parallel with and simultaneously with the computation of the filter output at each iteration. The filter includes a filter output processor (206) and a tap update processor (212) which respectively process, in parallel, the filter output and the coefficient updates for a subsequent iteration. The filter output processor and the tap update processor form their respective outputs at each iteration from input signal values at previous iterations stored in a filter input memory (203) and from tap coefficients stored in a filter taps memory (205). In even-numbered iterations only the even-numbered taps are updated and in odd-numbered iterations only the odd-numbered taps are updated.