Integrated Telecom Express, Inc.

Real Communications, Inc.

Young Way Liu

Ming-Kang Liu

Steve S Chen

Victor S Lee

Wen Chi Chen

John N Gross

Ta-Yung Lee

Wen-Ching Andy Chou

Chin-I Huang

Dean C Wang

A system that can be dynamically configured to achieve an optimal routing path for an end-to-end data link connection is disclosed. An optimal data path can be determined by a digital subscriber loop (DSL) user based on particular bandwidth requirements, data rate cost constraints, and/or data delay requirements. The data path can be set up to include one or more data routes, including the regular digital public switching telephone network (PSTN), a wide area networks (WAN), or virtual permanent circuit links via digital cross-connects (DCS).

Configurable digital subscriber loop access and end-to-end data and analog voice connection system

A device or interface driver is provided for permitting an operating system to utilize, configure and control a software modem having forward compatible and expandable functionality. In a preferred embodiment, the operating system is a Windows based system running on a host processing system such as a personal computer, and the modem is compatible with standards promulgated for ADSL. Conventional voice band modem control commands are also supported, so that the present invention for ADSL based modems is nevertheless compatible with existing modem applications programs. The new driver manages control information for configuring the bandwidth to be used in a data link established through a channel with an upstream transciever during an initialization process, and serves as a data pump for the software modem. The control information may be self-determined by a user of the host processing system or alternatively, automatically sensed, configured and monitored by such processing system.

Device driver for rate adaptable modem with forward compatible and expandable functionality

A high speed communications system is provided which uses a selectable, desirable portion of the total available bandwidth of a transmission channel. In a preferred embodiment, the invention is an ADSL compatible modem which selects a sub-set of the available downstream DMT sub-channels based on an evaluation of such sub-channels by appropriate signal processing circuitry. An analog front end (AFE) contains sub-band filtering causes an upstream transceiver to use only this selected number of available sub-channels for downstream data transmission. This reduces hardware costs and complexity while still preserving compatibility with applicable ADSL standards and providing a high speed data link. The target data rate of the modem can be further enhanced to the point of achieving full protocol capability by increasing or upgrading the AFEs, and/or the signal processing circuitry in order to increase the number of processable transmitted downstream sub-channels.

Forward compatible and expandable high speed communications system and method of operation

An ADSL physical transmission layer retrieves data to be transmitted from either a transmit data buffer, or a dummy cell buffer in the case when no actual data is being transmitted to maintain a continuous data stream in an ADSL data link. The ADSL physical transmission layer and an associated ATM protocol layer are implemented as an interrupt service routine and delayed procedure call respectively in an ADSL software modem application. Because the ATM protocol layer does not fill the transmit data buffer with dummy cell data, it is simpler and faster. Moreover, latency is minimized, and overall system throughput enhanced since the maximum latency is independent of any operating system latency, and is no greater than the size of the cell stored in the dummy cell buffer. The invention has significant potential for beneficial use in an ADSL based software modem where wide variations in performance and latency of computing systems pose engineering challenges in maintaining a continous data link between a real time transceiver and a non-real time operating system.

System and method for reducing latency in software modem for high-speed synchronous transmission

A high speed software modem is described which uses a selectable, desirable portion of the total available bandwidth of a transmission channel. In a preferred embodiment, the invention is implemented in a personal computer connected to an upstream transceiver through a channel supporting an Asymmetric Digital Subscriber Loop (ADSL) standard. The achievable target data rate of the modem is based on the capabilities of an analog front end (AFE) used in the modem, and a host processor within such personal computer. In particular, the modem AFE contains subband filtering which causes an upstream transceiver to use only a selected number of available sub-channels for downstream data transmission. The data rate of the modem is increased by upgrading the AFE or the host processor in order to increase the number of processable transmitted downstream sub-channels.

Software rate adaptable modem with forward compatible and expandable

A high speed modem is provided which uses a selectable, desirable portion of the total available bandwidth of a transmission channel. In a preferred embodiment, the invention is incorporated in a dedicated hardware circuit which is connected on one end to a data processor and on the other end to an upstream transceiver through a channel supporting an Asymmetric Digital Subscriber Loop (ADSL) standard. The achievable target data rate of the modem is based on the capabilities of an analog front end (AFE) used in the modem, and a signal processor within the dedicated hardware. In particular, the modem AFE contains subband filtering which causes an upstream transceiver to use only a selected number of available sub-channels for downstream data transmission. The data rate of the modem is increased by upgrading the AFE or the signal processor in order to increase the number of processable transmitted downstream sub-channels.

xDSL DMT modem using sub-channel selection to achieve scaleable data

An applications program is provided for permitting a user of a host processing system to dynamically control a modem having forward compatible and expandable functionality. In a preferred embodiment, the applications program is designed to run on a personal computer running the Windows.RTM. shell, and the modem is compatible with ADSL promulgated standards. As part of such program, initialization and detection routines determine the capabilities of an ADSL modem, including whether the same has been upgraded to have enhanced data throughput. A calibration routine measures the computing power available to the host processor, and based on this information and other relevant parameters determines nominal setup parameters for the modem. These parameters are stored in a Device Parameter Table so that they can be accessed by various application programs that may make use of such modem. A user of such program can at that time or thereafter alter the characteristics of the ADSL modem (including a target data rate) subject to availability of sufficiently powerful analog front end sampling circuitry and processing power.

Program for controlling DMT based modem using sub-channel selection to

A high speed modem is provided which targets the use of a selectable, desirable portion of the total available bandwidth of a channel for achieving a data rate which nevertheless far exceeds that of conventional voice-band modems. In a preferred embodiment, the invention is implemented in an Asymmetric Digital Subscriber Loop (ADSL), and the nominal data rate is achieved using an analog front end (AFE) with subband filtering which causes an upstream transceiver to use only a selected number of available sub-channels for downstream data transmission and allows slower sampling rate for the AFE. The data rate of the modem is increased in a multiplicative fashion through modular expansion of a bank of AFEs to increase the number of transmitted downstream sub-channels.

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La Mirada, CA, United States of America

Young Way Liu