Abstract: An improvement to a half duplex multipoint communication environment wherein a pilot tone enables a control device to maintain synchronization with a plurality of remote devices. The present invention employs a quantization noise compensator apparatus and method to supply a single bit, two level analog signal to drive a Voltage Controlled Crystal Oscillator (VCXO) in a remote device. The VCXO derives the sample rate signal for both transmit and receive devices, eliminating the requirement for a highly accurate digital to analog converter, thus reducing the cost and complexity of the system while allowing continuous synchronization between a control device and a plurality of remote devices.

Abstract: A roaming mechanism enabling a mobile station to roam between a first data packet network utilizing a Mobile IP Method (MIM) and a second data packet network utilizing a Personal Digital Cellular Mobility Method (PMM) is disclosed. A foreign agent (FA) is introduced into the PMM network for enabling a mobile station associated with the MIM network and currently roaming within the PMM network to communicate packet data with an associated home agent (HA). A home agent (HA) is further introduced into the PMM network for enabling a mobile station associated with the PMM network and currently roaming within the MIM network to communicate packet data with an associated FA or Mobile IP Client Emulator (MICE) currently serving the roaming mobile station.

Abstract: A nomadic router or translator enables a laptop computer or other portable terminal which is configured to be connected to a home network to be connected to any location on the internet or other digital data communication system. The router automatically and transparently re-configures the terminal to its new location and processes outgoing and incoming data. The router includes a processor which appears as the home network to the terminal, and appears as the terminal to the communication system. The terminal has a permanent address, the router has a router or translator address, and the terminal transmits outgoing data to the system including the permanent address as a source address. The processor translates the outgoing data by replacing the permanent address with the router address as the source address.

Abstract: An OFDM receiver determines (12; 27) the pulse response of a radio channel and locates (13; 14) its starting point, end point and the maximum and its value. The difference between the end point and the starting point gives the length of the pulse response. A guard interval time corresponding to the guard interval separating the OFDM symbols is set (17; 18) in the receiver in such a manner that it covers the most significant components of the pulse response. A slow and monotonous temporal shift of the pulse response between measurement rounds indicates an error in the sampling frequency. The error is corrected (23; 31) in such a manner that the pulse response shift is compensated for.

Abstract: A base station of a code division multiple access (CDMA)-based communications network (e.g., one conforming to the IS-95 standard) is sectorized such that, a first subset of CDMA channels are communicated using a first level of cell-site sectorization and a second subset of CDMA channels, different from the first subset, are communicated using a second level of cell-site sectorization, different from the first level. For example, the first set of CDMA channels may be the pilot and sync channels and the second subset of CDMA channels may be the access, paging, and traffic channels. In one set of implementations, at the first sectorization level, each cell site is omnidirectional (for the first subset of CDMA channels), while, at the second sectorization level, each cell site is divided into two or more sectors (for the second subset of CDMA channels). In this set of implementations, each cell site is assigned one pseudo noise (PN) offset and transmits one pilot channel.

Abstract: A packet of data is received from a LAN and transmitted over a WAN, by retaining the native LAN frame format of the packet during transmission across the WAN. Thus, LAN data may be transmitted over a SONET point-to-point link within a WAN network without the interim steps of creating ATM cells or other WAN transport packaging protocols. Instead, the LAN data may be transmitted directly over the SONET link as raw data, and reconstructed directly at the receiving end of the SONET link. A first buffer stores data from the LAN so that a corresponding packet size may be determined, and a second buffer stores data from the WAN to account for any speed difference between the LAN circuitry and WAN circuitry.

Abstract: In situations where 2.048 megabit E1 (32 channels) access to the customer premise is not available, the only option other than provisioning a 45 megabit T3 line to the customer premise is to provision two 1.544 megabit T1 (24 channels) lines, and inverse multiplex the customer's E1 signal onto the two T1 lines at the customer premises. At the network point-of-presence (POP), the applicable thirty-two channels of the two T1 lines are remultiplexed onto a single E1 line. The remaining sixteen channels of the two T1s are wasted. To prevent wasting these channels, the present invention provides an additional standard customer interface to enable transport of multiple 64 kilobit applications. The resulting N.times.64 kbit data stream can then be multiplexed onto the two T1 lines transporting the E1 signal. The inverse multiplexer at the network point-of-presence (POP), while remultiplexing the 32 T1 channels onto an E1 line, also extracts the DSOs carrying the N.times.

Abstract: A system for integrating multiple repeaters into a single collision domain employs both analog and digital circuitry to convey system-wide collision information to repeaters thereby allowing seamless integration of multiple repeaters into multiple hubs without requiring additional drivers or external glue logic. One signal line (CFSL) within each hub is used to aggregate collision information within the hub. Further, only one signal line (CFSS) is used to aggregate collision information between hubs. This latter signal line in conjunction with two intra-hub signal lines (COLZ and SNGLZ) distributes system-wide collision information to all of the repeaters in all of the hubs.

Abstract: A dynamic synchronous transfer mode network that comprises two ring topologies having opposite fiber direction. The first dynamic synchronous transfer mode ring topology has a plurality of nodes for receiving and transmitting frames. The time slots are dynamically allocated to the nodes and the first ring topology is adapted to transmit frames only in a first fiber direction. The second dynamic synchronous transfer mode ring topology also has a plurality of nodes in common with the first ring topology. The second ring topology only transmits frames in a second direction that is opposite the first fiber direction.

Abstract: A method of scheduling a plurality of data flows in a shared resource in a computer system, each of the data flows containing a plurality of data cells including the steps of providing a scheduler in the shared resource, initializing the scheduler to receive the plurality of data flows, receiving a first data flow in the scheduler, said first data flow having a first flow rate, receiving a second data flow in the scheduler, said second data flow having a second flow rate, scheduling, by the scheduler, the first data flow and the second data flow such that the first flow rate and the second flow rate are less than an available bandwidth in the shared resource and a relative error is minimized between an actual scheduling time and an ideal scheduling time on a per cell basis, and repeating the steps of receiving and scheduling.

Abstract: In a secure fast packet switch having a plurality of input ports and a plurality of output ports, a method of determining which port in the plurality of output ports data that is received on one input port in the plurality of input ports is to be sent to, the method including the steps of determining a physical layer address of a sending node, determining a physical layer address of a receiving node, determining an input port in the plurality of input ports that the data was received on, determining if the physical layer address of the sending node and the physical layer address of the receiving node are an allowed combination, determining the magnitude of the node identification number of the sending node, determining the magnitude of the node identification number of the receiving node, obtaining outbound port information from a first predetermined location in a data structure stored in a memory if the node identification number of the sending node is greater than the node identification number of the recei

Abstract: A network switcher for data transfer between a network communication unit and a plurality of nodes is provided. In this network switcher, the interface ports or MAC (media access control) addresses are divided into groups, and the data transfer is permitted only between those interface ports or MAC addresses within the same group. This feature can avoid a node-information signal whose destination address is not yet acknowledged to be transferred to all of the other interface ports beside the destination one. Conventionally, this drawback significantly degrades the performance of the overall network system. This network switcher allows an improvement on the performance of network systems that has a number of nodes.

Abstract: When some terminal makes a connection request to a first terminal, a control apparatus of an ATM exchange refers to a band management table to check if this first terminal is busy. When the first terminal is busy, the control apparatus executes a call connection process of establishing connection to the first terminal. When the first terminal is not busy, the control apparatus reads a substitute terminal for the first terminal from a registration table and executes a connection process for this substitute terminal.

Abstract: Time dispersion of a signal that has been received from a channel is measured by utilizing metrics to determine the energy inside an equalizer window and outside of the equalizer window. In one embodiment, the estimate of the energy outside the window is a difference between residual interference estimates. In another embodiment, the estimate of the energy outside the window is a difference between residual impulse response power estimates.

Abstract: A system and method for managing elements of information at a network node received from a user access node. An access node includes a user/network interface (UNI), and a core network node includes a cell filtering unit. The UNI includes a measuring unit, which measures the actual momentary bit rate of a connection between the UNI and the core node, and a priority level computing unit, which computes the priority level of each cell using the measured bit rate and an established nominal bit rate (NBR). NBR represents an expected, but not guaranteed, bit rate associated with a particular user or connection. The connection may be a real-time or a non-real-time connection. A scheduling unit of a node accepts or discards an arriving cell based on the occupancy of a real-time buffer and a non-real-time buffer provided at the node.

Abstract: A method and apparatus is provided for demodulating direct sequence, spread spectrum CDMA signals in the presence of unknown spread-spectrum multiuser interference and additive white Gaussian noise, using only the available received signal and the predetermined, pre-stored spreading code assigned to user of interest. The method includes the steps of sampling the incoming channel signal at the chip rate to produce an incoming sampled signal, supplying the incoming sampled signal to filter having tap coefficients corresponding to an auxiliary vector, the filter having an output representing an estimate of the transmitted symbol, providing the output to a sign determining components and determining the sign of the output to thereby generate the detected symbol.

Abstract: A network architecture and service platform for providing virtual private network services ("VPN") over an ATM network. The architecture provides services for voice, video, and data traffic among multiple VPN customers over a shared ATM network by implementing intelligent control devices to perform enhanced processing of ATM call setup messages, including validations and routing translations. Hierarchical routing mechanisms provided by ATM, along with customized customer addressing schemes, are used to overlay customer VPNs as higher-level networks onto the shared ATM network. The control devices translate customer ATM VPN address to internal ATM network addresses. The ATM switch network then performs lower-level network processing, using internal network addressing, to setup a virtual connection for a VPN call. The intelligent control devices may also explicitly state the end-to-end route.

Abstract: A communications device is attachable to a host computer. The device transmits, receives, and stores entire files of data with their attributes needed for recognition, reading, and writing by a proper application program. Logical devices such as processors, filters, locks, and telecommunications devices in the communications device include electronic circuits for assembling message files and for transmitting selected datafiles to and from an attached host computer. The communications device also transmits, stores and receives with respect to a second remote device or a computer with a modem. The device permits file communication without permitting access to its own host computer or workstation. The device may transmit while the computer is off, and without logging into the second computer provided with the same type of device. The device facilitates point to point communication of data files in a secure manner for creation of virtual private networks between individuals over public telephone networks.

Abstract: A system and method for determining a root cause of error activity in a network is described herein. Root cause analysis includes the correlation between reported error activity for path, line and section entities along a provisioned channel in the network. Root causes can also be identified based upon the correlation of simultaneous error activity on various signal transport levels. Finally, root cause analysis can correlate error activity along various path entities.

Abstract: A vehicle multiplex communication apparatus having such a transmission arrangement that the rate of transmission of information over a common bus is limited to a prescribed rate without limiting the number of additional control elements provided in a vehicle. The communication apparatus has the common bus provided in the vehicle and a plurality of central control units connected to the common bus. The central control units transmit information in accordance with a first information protocol between the common bus and constitutional controlled equipment of the vehicle or control elements for controlling the controlled equipment. The communication apparatus also has an information collection control unit connected to at least one of the plurality of central control units through a simpler bus.