Broadcom Corporation

Anders Hebsgaard

Lisa Voigt Denney

David Hartman

Mark Dale

Robert J Lee

Thomas J Quigley

Kevin Lee Miller

Alan Y Kwentus

Alan Gin

Dorothy D Lin

David Dworkin

Kelly Brian Cameron

Steven T Jaffe

Stephen Edward Krafft

Jen-chieh Chien

L Randall Mote, Jr

Thuji Simon Lin

Rocco J Brescia, Jr

Rocco Brescia

Kenneth G Zaleski, Ii

Joyce Wang

Jen-chieh (Jack) Chien

Cho-Hsin J Wang

Joey Y Chen

In a satellite gateway, data is transmitted over a downstream channel at different throughput rates. Data destined for each subscriber/receiver is assigned a throughput rate depending upon the downstream signal quality of that subscriber/receiver. The downstream data is parsed to extract data packets. The data packets are then loaded into packet queues based on an identifier within such packets. The queues represent a bandwidth efficiency or throughput rate that can be currently tolerated by specific subscribers that may also be based on the current signal quality at a subscriber location. The parsed data traffic is processed based on the profile of the plurality of profiles to produce processed data traffic, and transmitted from the packet queues over a downstream channel.

Downstream time domain based adaptive modulation for DOCSIS based applications

A downstream adaptive modulation system and method. The downstream adaptive modulation system comprises a wireless access termination system and one or more wireless modems. The wireless access termination system includes a plurality of queues and a parser. The parser parses data traffic onto the plurality of queues. Each queue is associated with a different coding and modulation scheme. Each of the one or more wireless modems receives data traffic from the plurality of queues based on the wireless modem's ability to demodulate and decode the signal from each of the plurality of queues. When a wireless modem experiences a change in signal strength, the present invention enables the wireless modem to adapt to data from other queues to compensate for the change in signal strength. Thus, if the signal strength improves over a period of time, the wireless modem may receive data at a higher order modulation and FEC code rate. If the signal strength weakens over a period of time, the wireless modem may receive data at a lower order modulation and FEC code rate.

Downstream adaptive modulation in broadband communications system

A modified ranging request in a broadband communications system. The modified ranging request includes a header, a management message header attached to the header, a management message payload attached to the management message header, and a CRC attached to the management message payload. The management message header enables bandwidth requests to be made by subscriber equipment without contention. The management message header also includes state of health information on the status of a downstream transmission for enabling a central location to determine how to assign subscribers to queues in an adaptive modulation scheme.

Modified range requests enabling bandwidth requests and state of health reporting

A method and apparatus for performing trellis coded modulation of signals for transmission on a TDMA channel of a cable network, such as a DOCSIS cable network, is provided. In an embodiment, an upstream modulator portion of a cable modem receives burst data, selectively encodes the burst data for trellis coded modulation to generate encoded symbols, and modulates the encoded symbols for selective transmission over a time division multiple access (TDMA) channel or a synchronous code division multiple access (S-CDMA) channel of the cable network.

Method and apparatus for performing trellis coded modulation of signals for transmission on a TDMA channel of a cable network

A plurality of CMTS devices are linked together and synchronized to facilitate communication between the respective CMTS devices and respective downstream cable modems. According to one embodiment of the invention, one of the CMTS devices is designated as a master device, and the other CMTS devices are designated as slave devices. The respective CMTS devices are connected to each other by means of a synchronization bus. The master CMTS device then generates and broadcasts a future time stamp value, which is received by the respective slave CMTS devices. When the time stamp counter in the master CMTS device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave CMTS devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the CMTS devices are synchronized.

Synchronization of multiple base stations in a wireless communication system

A plurality of base station devices are linked together and synchronized to facilitate communication between the respective base station devices and respective downlink subscriber stations. According to one embodiment of the invention, one of the base station devices is designated as a master device, and the other base station devices are designated as slave devices. The respective base station devices are connected to each other by means of a synchronization bus. The master base station device then generates and broadcasts a future time stamp value, which is received by the respective slave base station devices. When the time stamp counter in the master base station device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave base station devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the base station devices are synchronized.

Methods for the synchronization of multiple base stations in a wireless communication system

Upstream requests such a bandwidth requests, are processed by CMTS out of order on a priority basis to reduce latency in responding to the request. Specifically, a cable modem termination system (CMTS) is connected to a plurality of cable modems by a cable plant. The CMTS has a burst receiver adapted to be connected to the cable plant to process upstream data packet units and bandwidth requests transmitted by the cable modems. Each packet includes a header that uniquely distinguishes the bandwidth requests from other data types. Packet data units are arranged in a first memory queue. Bandwidth requests are arranged in a second memory queue. The headers of the packets processed by the burst receiver are inspected as they arrive at the CMTS to determine if the packets are packet data units or bandwidth requests. Packet data units are routed to the first memory queue. Bandwidth requests are routed to the second memory queue. Bandwidth allocation MAP messages are generated from the bandwidth requests stored in the second queue and transmitted downstream to the cable modems. The packet data units stored in the first queue are coupled to a data output for further distribution.

Apparatus for the reduction of uplink request processing latency in a wireless communication system

Method and apparatus for the reduction of upstream request processing latency in a cable modem termination system

A timing recovery system and method for accelerated clock synchronization of remotely distributed electronic devices is provided. The system includes a phase locked loop, a linear estimator and control logic. The method includes sampling a clock signal received from an electronic device, applying a linear estimation technique to estimate the frequency and phase of the received signal and providing those estimates to a phase locked loop to accelerate the phase locked loop acquisition rate and secure signal lock quickly.

System and method for accelerated clock synchronization of remotely distributed electronic devices

In a DOCSIS based satellite gateway data is transmitted over a single downstream channel, at different throughput rates. Data destined for each subscriber/receiver is assigned a throughput rate depending upon the downstream signal quality of that subscriber/receiver. To accomplish this, the downstream DOCSIS MAC data is parsed to extract DOCSIS packets. The DOCSIS packets are then loaded into packet queues based on an identifier within such packets such as the MAC destination address or SID. Each of the queues represents a bandwidth efficiency or throughput rate that can be currently tolerated by specific subscribers based on the current signal quality being experienced at the subscriber location. A PHY-MAP describing the downstream data structure to be transmitted and inserted into the downstream data. Data is extracted from the packet queues in queue blocks as defined by the PHY-MAP. The queue blocks are modulated with transmission parameters appropriate for each queue block and transmitted to the DOCSIS based satellite modems. The satellite modems extract the PHY-MAP from the downstream data and use the information contained in it to demodulate and decode the queue for which they have sufficient downstream signal quality. Satellite modems measure and transmit downstream signal quality to the satellite gateway to be used to assigned traffic to the appropriate queues.

A method for synchronizing counters in a wireless terminal device with those of an administrative device. With each increment of the frame counter in a wireless terminal device, the wireless device minislot counter advances by an amount equal to the number of minislots per frame. Likewise, with each increment of the frame counter, the wireless device's timestamp counter is incremented by the number of timestamps per frame. This continues until the counters at the wireless device are within one frame of the administrative device's counters. The minislot counter is then incremented. With each increment of the minislot counter, the timestamp counter is incremented by an amount equal to the number of timestamps per minislot. This continues until the wireless devices counters are within a minislot of the administrative device's counters. The timestamp counter is then incremented until the wireless device's counters match those of the administrative device.

Method for synchronization of wireless devices through accelerated advance of counters

A method for synchronizing counters in a terminal device, such as a cable modem in a DOCSIS-based system, with those of an administrative device, such as a headend. A cable modem advances its frame counter. With each increment of the frame counter, the cable modem's minislot counter advances by an amount equal to the number of minislots per frame. Likewise, with each increment of the frame counter, the cable modem's timestamp counter is incremented by the number of timestamps per frame. This continues until the counters at the cable modem are within one frame of the headend's counters. The minislot counter is then incremented. With each increment of the minislot counter, the timestamp counter is incremented by an amount equal to the number of timestamps per minislot. This continues until the cable modem's counters are within a minislot of the headend's counters. The timestamp counter is then incremented until the cable modem's counters match those of the headend.

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Lawrenceville, GA, United States of America

Anders Hebsgaard