Pulse or digital communications – Transceivers – Modems
Reexamination Certificate
2000-05-04
2004-06-15
Tran, Khai (Department: 2731)
Pulse or digital communications
Transceivers
Modems
Reexamination Certificate
active
06751254
ABSTRACT:
BACKGROUND OF THE INVENTION
Definitions
The following definitions are employed throughout the detail discussion:
activating station—the DTE, DCE and other associated terminal equipment which originates an activation of an xDSL service;
answering station—the DTE, DCE and other associated terminal equipment which answers a call placed on the PSTN (GSTN);
carrier set—a set of one or more frequencies associated with a PSD mask of a particular xDSL Recommendation;
CAT3—cabling and cabling components designed and tested to transmit cleanly to 16 MHz of communications. Used for voice and data/LAN traffic to 10 megabits per second;
CAT5—cabling and cabling components designed and tested to transmit cleanly to 100 MHz of communications;
communication method—form of communication sometimes referred to as modems, modulations, line codes, etc.;
downstream—direction of transmission from the xTU-C to the xTU-R;
Galf—an octet having the value 81
16
; i.e., the ones complement of an HDLC flag;
initiating signal—signal which initiates a startup procedure;
initiating station—DTE, DCE and other associated terminal equipment which initiates a startup procedure;
invalid frame—frame that has fewer than four octets between flags, excluding transparency octets;
message—framed information conveyed via modulated transmission;
metallic local loop—communication channel 5, the metallic wires that form the local loop to the customer premise;
responding signal—signal sent in response to an initiating signal;
responding station—station that responds to initiation of a communication transaction from the remote station;
session—active communications connection, measured from beginning to end, between computers or applications over a network;
signal—information conveyed via tone based transmission;
signaling family—group of carrier sets which are integral multiples of a given carrier spacing frequency;
splitter—combination of a high pass filter and a low pass filter designed to split a metallic local loop into two bands of operation;
telephony mode—operational mode in which voice or other audio (rather than modulated information-bearing messages) is selected as the method of communication;
transaction—sequence of messages, ending with either a positive acknowledgment [ACK(1)], a negative acknowledgment (NAK), or a time-out;
terminal—station; and
upstream: The direction of transmission from the xTU-R to the xTU-C.
Abbreviations
The following abbreviations are used throughout the detailed discussion:
ACK—Acknowledge Message;
ADSL—Asymmetric Digital Subscriber Line;
CCITT—International Telegraph and Telephone Consultative Committee;
CDSL—Consumer Digital Subscriber Line;
DSL—Digital Subscriber Line;
FSK—Frequency Shift Keying;
GSTN—General Switched Telephone Network (same as PSTN);
UDSL—High bit rate Digital Subscriber Line;
HSTU-C—handshaking portion of the xDSL central terminal unit (xTU-C);
HSTU-R—handshaking portion of the xDSL remote terminal unit (xTU-R).
ISO—International Organization for Standardization;
ITU-T—International Telecommunication Union—Telecommunication Standardization Sector;
NAK—Negative Acknowledge Message;
NTU—Network Termination Unit (Customer premise end);
PBO—Power Back Off;
PME—Power Management Exchange
PMM—Power Measurement Modulation;
PMMS—Power Measurement Modulation Session;
POTS—Plain Old Telephone Service
PSD—Power Spectral Density;
PSTN—Public Switched Telephone Network;
RADSL—Rate Adaptive DSL;
VDSL—Very high speed Digital Subscriber Line;
xDSL—any of the various types of Digital Subscriber Lines (DSL);
xTU-C—central terminal unit of an xDSL; and
xTU-R—remote terminal unit of an xDSL.
1. Field of the Invention
The present invention is directed to a high speed communications device, such as, for example, but not limited to, a modem, a cable modem, a xDSL modem, a satellite communication system, a point-to-point wired or wireless communication system, which includes a handshaking or initializing protocol, and in particular, to an apparatus and method that provides means to robustly select measurement procedures and robustly report the results of such measurement procedures.
2. Discussion of Background and other Information
One of the important functionalities of the various xDSL schemes is to accurately control the amount of transmit power used on a specific xDSL line. Since each local loop used for xDSL has unique parameters, such as, for example, attenuation, interference, crosstalk, etc, it is desirable to accurately measure those parameters before blindly transmitting large amounts of power into the loop. Heretofore, each xDSL scheme has used it's own proprietary style of power measurement and control, with varying degrees of measurement and control.
Additionally, the power control measurement procedures of the prior art were typically used after the xDSL modulation had started, with large amounts of power already being trasmitted.
Accordingly, there is a need for an apparatus and method that provides means to robustly select measurement procedures and robustly report the results of such measurement procedures, so as to minimize the amount of transmission power used to transmit data.
The ITU-T has published recommended methods for initiating data communication over voice band channels. The following three Recommendations have been produced, the subject matter of which is expressly incorporated herein by reference in their entirety:
1) Recommendation V.8, entitled “Procedures For Starting Sessions Of Data Transmission Over The General Switched Telephone Network”, published in September, 1994;
2) Recommendation V.8bis, entitled “Procedures For The Identification And Selection Of Common Modes Of Operation Between Data Circuit-Terminating Equipments (DCEs) And Between Data Terminal Equipments (DTES) Over The General Switched Telephone Network”, published in August, 1996; and
3) Recommendation G.994.1, entitled “Handshake Procedures For Digital Subscriber Line (DSL) Transceivers”, published in June 1999.
It is noted that document (3) is the final version of Temporary Document MA-006 that was published in March, 1999.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a uniform power measurement procedure that can be used for all xDSL schemes. Another object of the instant invention is to perform the uniform power measurement procedure prior to the selection of the specific xDSL scheme. The procedure of the instant invention may be implemented as an extension to an xDSL handshaking and selection procedure, such as, but not limited to, that shown in commonly assigned U.S. patent application Ser. Nos. 09/217,556 filed on Dec. 21, 1998 and/or 09/281,813 filed on Mar. 31, 1999, and/or ITU-T Recommendation G.994.1, published in June, 1999. Integrating the power control and measurement procedure with the xDSL selection procedure allows a more accurate selection of the particular xDSL modulation scheme, based on the power measurement results. The present invention also allows for a more accurate determination of the minimum needed frequency dependent transmission power during a data transmission mode.
According to an object of the present invention, an apparatus is disclosed for determining transmission parameters while initializing a communication link. A parameter indicating device, that is associated with an initiating communication device, transmits first transmission parameters that can be used by the responding communication device to a responding communication device. In response to the transmitted first transmission parameters, a measurement receiving section, that is associated with the initiating communication device, receives first signals issued by the responding communication device.
According to an advantage of the invention, the initiating communication device also includes a parameter receiving device that receives, from the responding communication device, second transmission parameters that can be used by the initiating communication device, and a measurement transmission section that transmits second signals to the resp
Panasonic Communications Co. Ltd.
Tran Khai
LandOfFree
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