Abstract: A device and method are disclosed for correctly restoring a read clock when there are a plurality of STM data stream transmission sources. In a CES device of an ATM communication system, ATM cells from respective connections, which are to be delivered to the same outgoing line, are accumulated in a reassembly buffer memory and a PLO control unit aggregates the amount of ATM cells accumulated in the reassembly buffer memory for each connection. Subsequently, the PLO control unit calculates the frequency of a read clock based on the amount of accumulated ATM cells for each connection. A PLO restores the read clock which is applied to read data from the reassembly buffer memory for delivery to an STM network.
Abstract: Provided are a method, system and article of manufacture for data communications. A transmitter transmits a plurality of packets, wherein each packet is transmitted after a time interval. A receiver receives at least one part of the plurality of packets. The receiver determines whether all parts of a packet are received before expiration of the time interval, wherein the received packet is valid if all parts are received before the expiration of the time interval.
Type:
Grant
Filed:
May 1, 2002
Date of Patent:
September 5, 2006
Assignee:
International Business Machines Corporation
Abstract: In a network node having one or more packet processors and at least one CPU required to process specific types of packets, a system for managing the specific types of packets for CPU processing has one or more packet processors enabled to sort the specific types of packets into two or more categories of different priority for processing; and a queue set for queuing the sorted packets according to priority ahead of the CPU. The system is characterized in that the CPU processes the queued packets according to priority. In a special case the queues are a part of network access controller (NAC). Also in some cases a software component is provided for configuring the hardware.
Abstract: A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter (10) of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver (400) of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.
Type:
Grant
Filed:
March 4, 2002
Date of Patent:
August 29, 2006
Assignee:
Agency for Science, Technology and Research
Inventors:
Ying-Chang Liang, Francois Chin Po Shin, Appukuttan Nair Saraswathy Amma Madhukumar
Abstract: A network processor is used for the routing of objects in non-data networking applications. The processor utilizes the Open Shortest Path First (OSPF) algorithm to capitalize on the benefits of data control for object traffic control and costs. A network processor is used at each point in a grid represented by intersecting paths. One or more routing tables are embedded in each network processor. Each routing table describes links with other network processors in the grid to which the network processor is interconnected. A cost factor is associated with each link and is constantly updated by the OSPF as new information becomes available. If a link or route becomes unavailable, the cost is set at infinity. The system then creates an alternative path for the object between a source and the desired destination that bypasses the unavailable link or route.
Type:
Grant
Filed:
May 3, 2002
Date of Patent:
August 29, 2006
Assignee:
International Business Machines Corporation
Inventors:
Charles Steven Lingafelt, Francis Edward Noel, Jr., Ann Marie Rincon
Abstract: A method for finding shared risk diverse paths is disclosed. The method includes receiving route information at a node and running a shortest path algorithm to identify a first path. A shared risk metric is assigned to links and nodes with the first path. The method further includes running the shortest path algorithm with the shared risk metrics assigned to identify a second path and comparing the first and second paths. New shared risk metrics are assigned to links and nodes in the second path if the first and second paths are not diverse. The second path then becomes the first path and the algorithm is repeated.
Abstract: Techniques for transmitting data using a number of diversity transmission modes to improve reliability. At a transmitter, for each of one or more data streams, a particular diversity transmission mode is selected for use from among a number of possible transmission modes. These transmission modes may include a frequency diversity transmission mode, a Walsh diversity transmission mode, a space time transmit diversity (STTD) transmission mode, and a Walsh-STTD transmission mode. Each diversity transmission mode redundantly transmits data over time, frequency, space, or a combination thereof. Each data stream is coded and modulated to provide modulation symbols, which are further processed based on the selected diversity transmission mode to provide transmit symbols. For OFDM, the transmit symbols for all data streams are further OFDM modulated to provide a stream of transmission symbols for each transmit antenna used for data transmission.
Abstract: A fixed wireless system (FWS) utilizing Orthogonal Frequency Division Multiplexing (OFDM) communication techniques is spectrally efficient and responsive to communications involving both voice and high speed data, such as Internet data. The FWS includes a wireless base unit; a plurality of fixed wireless remote units; a plurality of wireless data traffic channels available between the wireless base unit and the plurality of fixed wireless remote units; and a plurality of wireless voice traffic channels available between the wireless base unit and the plurality of fixed wireless remote units. Each wireless traffic channel is identifiable by a unique combination of frequency and time slots. Each wireless data traffic channel is used for carrying high speed data in addressed data packets to and from the plurality of fixed wireless remote units.
Type:
Grant
Filed:
June 14, 2000
Date of Patent:
August 22, 2006
Assignee:
Cingular Wireless II, LLC
Inventors:
Siavash Alamouti, Jeffrey Battin, David B. Gibbons, James Timothy Golden, Michael R. Hirano, Elliott Hoole, Mary Jesse, Robert Lee Maxwell, Steven E. McMeekin, David J. Nix, David James Ryan, Gregory J. Veintimilla, Hongliang Zhang
Abstract: Frequency-dependent cancellation separates a plurality of interfering signals received by a plurality of receivers. Received wideband single-carrier signals or multicarrier signals are separated into a plurality of narrowband subcarriers. Sub-carrier frequencies and frequency-band characteristics may be selected with respect to channel characteristics (e.g., coherence bandwidth, interference, etc.). A cancellation circuit provides complex weights to the sub-carrier components. Weighted components associated with each sub-carrier frequency are combined to separate a plurality of interfering signals. Optionally, a plurality of the separated subcarriers may be combined to reconstruct at least one transmitted single-carrier signal from a plurality of frequency components.
Abstract: The present invention provides a method for adaptive diversity combining for Wide Band Code Division Multiple Access (W-CDMA) comprising: splitting multi-path interference into Iknown and Iunknown components, precomputing said Iknown interference components, iteratively estimating channel interference after removing Iknown components of the multi-path interference from the pilot symbols, using the convergence/divergence of the iteration as an indicator of the channel condition, and The instant invention also provides a system and configured computer program product for carrying out the above method.
Abstract: A system and methods are shown for traffic shaping and congestion avoidance in a computer network such as a data-over-cable network. A headend of the data-over-cable system includes a traffic shaper configured to calculate a packet arrival rate from a cable modem and a traffic conditioner configured to calculate an average queue size on an output interface to an external network. For example, the traffic shaper compares the packet arrival rate to three packet arrival thresholds including a committed rate threshold, a control rate threshold and a peak rate threshold. If the calculated packet arrival rate falls between the committed threshold and control rate threshold, the traffic shaper applies a link layer mechanism, such as a MAP bandwidth allocation mechanism, to lower the transmission rate from the cable modem.
Type:
Grant
Filed:
August 27, 2001
Date of Patent:
August 8, 2006
Assignee:
3Com Corporation
Inventors:
Michael Freed, Satish Amara, Michael Borella
Abstract: A system and method are presented for digital communication via a time division multiplexed serial data stream. A serial communication system according to the present invention includes a serial communication controller having a set of functional units each configured to perform a specific function of a serial communication protocol. The functional units are operably coupled in series in order to produce digital data according to the serial communication protocol. The set of functional units operates alternately upon an active one of the multiple serial data channels within the time division multiplexed serial data stream. Each functional unit may be a state machine including one or more programmable registers for storing state information which determines the operating state of the functional unit.
Type:
Grant
Filed:
January 11, 1999
Date of Patent:
August 8, 2006
Assignee:
Advanced Micro Devices, Inc.
Inventors:
William W. Freitag, Jr., Daniel B. Reents
Abstract: A method is used for setting a R-P link for data transmission/reception in a mobile communication system and for setting a R-P link between packet control function (PCF) and packet data serving node (PDSN) in a mobile communication system that connects a radio network with a packet network. The method first transmits a response request message from the PCF to identify the status of two or more PDSNs in the system, then measures the RTDs of those PDSNs responded to the response request message. The method subsequently prepares a list of PDSNs that satisfy a reference value among the measured RTDs and determines whether the subscriber's PDSN exists in the list of PDSNs. Finally, the method performs a R-P link setup using the prepared list of PDSN in accordance with a determined result.
Abstract: Systems and methods for performing congestion detection and connection admission control for a communications network utilizing the observed one-way delay of packets transmitted through the network are described. Embodiments of the present invention provide endpoints on the network, which can anticipate congestion accurately enough to prevent packet loss and excess delay while, at the same time, fully utilizing network resources. In one embodiment of the present invention, a communications service provider replaces conventional tandem switches in a public switched telephone network with Internet protocol (IP) tandems. The IP tandem includes a media gateway, which performs congestion admission control for voice over IP (VoIP) communications. When delay in the communications network exceeds a delay threshold, the media gateway may reject the communications request or may route the request over an alternative channel.
Abstract: A method of routing data from a client through one or more load-balancing nodes to a selected load-balanced server among a plurality of servers in a network involves: receiving, at a last load balancing node associated with a selected server among the plurality of servers, a first packet of a server reply to a request from the client; setting a first flag value in the first packet of the server reply; storing one or more identifiers of ingress interfaces on which the packet arrives, in a send path list for server load balancing, as the first packet of the server reply is routed from the last load balancing node to the client using hop-by-hop decisions; receiving one or more subsequent packets of the client request; setting a second flag value in each of the subsequent packets; and forwarding the subsequent packets to the selected server only on a route that is defined by the send path list and without hop-by-hop routing decisions.
Abstract: A DSL 5 is connected between an exchange device 3 and an IAD1 to which DSL subscriber terminals 2-1 through 2-n are connected, and the exchange device 3 is equipped with a VMG 4 for terminating an ATM cell multiplexed over the DSL 5, a voice packet transmitted as multiplexed over the DSL 5 is directly terminated at the exchange device 3, which in turn converts the voice packet into a packet according to an existing exchange device interface 8, so that DSL subscribers can be accommodated in the exchange device 3 directly and also exchange device software for operating the exchange device 3 can control call processing without knowing about a device under the control of a subscriber control unit, as a result, user burdens can be mitigated.
Abstract: A telecommunications method and system of floor control, for enabling at least one conference participant to access a shared object or resource for purposes of input. A floor control command signal establishes at least one floor control policy, and the floor control command signal includes a floor control language script for automatically determining the access. This access is determined based upon factors such as access requests and prior access history, without need for a floor chair.
Abstract: An enhanced radio link protocol (RLP) in a wireless access network that is network aware is disclosed. The RLP increases radio link quality by various ARQ mechanisms. The RLP framing structure is included that supports and enables at least network layer packet boundary detection, dynamic and adaptive ARO schemes for QoS support on a per-packet basis, and a flexible RLP frame structure for fast adaptation to physical layer channel rate/RLP frame sizes. Optional uses include supporting negative acknowledgment (NAK) based ARQ.
Abstract: A channel access system is described in which a number of slots within a contention window are available for assignment to streaming data transmitters. The other slots are selected by the other transmitters according to a CSMA/CA transmit protocol.
Abstract: Techniques to search for pilots over code space in a CDMA system. In one aspect, the pilot search is performed using a number of substages, and the search windows for each substage are selected such that the relevant code space is searched while reducing search time. In one specific implementation, two substages are used to search for pilots. The detect substage searches through (e.g., fixed-size) search windows to detect for peaks in the received signal. The dwell substage then searches through (e.g., variable-size) search windows to re-evaluate the detected peaks and remove noise peaks. The dwell windows may be formed such that a code space as small as possible is searched (to reduce search time) but large enough to account for possible drift in the detected peaks. Variable number of peaks may be provided by the dwell substage for the variable-size dwell windows.
Type:
Grant
Filed:
October 25, 2001
Date of Patent:
August 1, 2006
Assignee:
Qualcomm Incorporated
Inventors:
Remi Gurski, Serguei A. Glazko, Raghu Challa