Method of distributed loop control for a multicarrier telephony transport

• US 6,594,322 B2
• Filed: 09/15/1999
• Issued: 07/15/2003
• Est. Priority Date: 02/06/1995
• Status: Expired due to Term

• Current Assignee: HTC Corporation
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Dapper, Mark J., Geile, Michael J., Hill, Terrance
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US09/396,843
• Publication Number:
  US 20020102937A1
• Time in Patent Office: 1,399 Days
• Field of Search: 455/5.1, 455/208, 455/86, 370/330, 370/334, 370/480, 370/249, 370/210, 375/208, 375/344, 375/219, 331/1.A, 327/99, 340/870.18, 329/308
• US Class Current: 375/330
• CPC Class Codes: G06F 17/14 Fourier, Walsh or analogous domain transformations , e.g. Laplace, Hilbert, Karhunen-Loeve, transforms for correlation function computation G06F17/156; spectrum analysers G01R23/16
• CPC Class Codes: G06F 17/142 Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/356 Unequal error protection [UEP]
• CPC Class Codes: H04B 10/272 Star-type networks or tree-type networks
• CPC Class Codes: H04H 20/69 Optical systems
• CPC Class Codes: H04H 20/77 using carrier waves
• CPC Class Codes: H04H 20/78 CATV [Community Antenna Television] systems
• CPC Class Codes: H04H 20/79 using downlink of the CATV systems, e.g. audio broadcast via CATV network
• CPC Class Codes: H04H 20/80 having frequencies in two or more frequency bands, e.g. medium wave and VHF
• CPC Class Codes: H04H 60/11 Arrangements for counter-measures when a portion of broadcast information is unavailable
• CPC Class Codes: H04H 60/86 accessed over CATV networks
• CPC Class Codes: H04H 60/96 CATV systems for accessing the Internet H04H60/86
• CPC Class Codes: H04H 60/97 using uplink of the CATV systems
• CPC Class Codes: H04J 14/0298 with sub-carrier multiplexing [SCM]
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04K 3/226 Selection of non-jammed channel for communication spectrum sharing arrangements H04W16/14; selection of wireless resources by user or terminal H04W72/02
• CPC Class Codes: H04K 3/255 based on redundancy of transmitted data, transmission path or transmitting source
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0045 : Arrangements at the receiver end
• CPC Class Codes: H04L 1/0057 : Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0071 : Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/24 : Testing correct operation
• CPC Class Codes: H04L 12/10 : Current supply arrangements
• CPC Class Codes: H04L 12/12 : Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 12/2801 : Broadband local area networks
• CPC Class Codes: H04L 12/44 : Star or tree networks
• CPC Class Codes: H04L 2001/0093 : Point-to-multipoint
• CPC Class Codes: H04L 2027/0036 : using a recovered symbol clock
• CPC Class Codes: H04L 2027/0057 : quadrature phase
• CPC Class Codes: H04L 2027/0067 : Phase error detectors
• CPC Class Codes: H04L 25/03866 : using scrambling
• CPC Class Codes: H04L 27/2601 : Multicarrier modulation systems
• CPC Class Codes: H04L 27/2614 : Peak power aspects
• CPC Class Codes: H04L 27/2631 : with polyphase implementation
• CPC Class Codes: H04L 27/2634 : Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• CPC Class Codes: H04L 27/2647 : Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/2652 : with polyphase implementation
• CPC Class Codes: H04L 27/26524 : Fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators in combination with other circuits for demodulation
• CPC Class Codes: H04L 27/2654 : Filtering per subcarrier, e.g. filterbank multicarrier [FBMC]
• CPC Class Codes: H04L 27/2655 : Synchronisation arrangements
• CPC Class Codes: H04L 27/2657 : Carrier synchronisation
• CPC Class Codes: H04L 27/2662 : Symbol synchronisation
• CPC Class Codes: H04L 27/34 : Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04L 41/0213 : Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 41/064 : involving time analysis
• CPC Class Codes: H04L 41/0896 : Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities flow or congestion control using dynamic resource allocation, e.g. in-call renegotiation, H04L47/76
• CPC Class Codes: H04L 43/00 : Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/022 : by sampling
• CPC Class Codes: H04L 43/067 : using time frame reporting
• CPC Class Codes: H04L 43/0811 : by checking connectivity
• CPC Class Codes: H04L 43/0817 : by checking functioning
• CPC Class Codes: H04L 43/0823 : Errors, e.g. transmission errors
• CPC Class Codes: H04L 43/0829 : Packet loss
• CPC Class Codes: H04L 43/0847 : Transmission error
• CPC Class Codes: H04L 43/0852 : Delays
• CPC Class Codes: H04L 43/0858 : One way delays
• CPC Class Codes: H04L 43/0864 : Round trip delays
• CPC Class Codes: H04L 43/0882 : Utilisation of link capacity
• CPC Class Codes: H04L 43/16 : Threshold monitoring
• CPC Class Codes: H04L 5/0007 : the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 : Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0044 : allocation of payload
• CPC Class Codes: H04L 5/023 : Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04L 5/14 : Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/143 : for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1484 : operating bytewise
• CPC Class Codes: H04M 7/006 : Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42
• CPC Class Codes: H04M 9/027 : Frequency division multiplex systems
• CPC Class Codes: H04N 21/2221 : being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/2383 : Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/2385 : Channel allocation H04N21/266 takes precedence; Bandwidth allocation H04N21/24 takes precedence ; allocation of channels according to the instantaneous demands of the users in time-division multiplex systems H04J3/1682; admission control, resource allocation in open networks H04L12/5692; arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896; negotiating bandwidth in wireless networks H04W28/16
• CPC Class Codes: H04N 21/2402 : Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/4382 : Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/6118 : involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6137 : involving transmission via a telephone network, e.g. POTS
• CPC Class Codes: H04N 21/6168 : involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/17309 : Transmission or handling of upstream communications
• CPC Class Codes: H04N 7/22 : Adaptations for optical transmission
• CPC Class Codes: H04W 24/00 : Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/08 : Testing, supervising or monitoring using real traffic
• CPC Class Codes: Y02D 30/50 : in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method of distributed loop control is described. The method includes receiving at a service unit downstream control and telephony information modulated on orthogonal carriers in a first frequency bandwidth over a distribution network. The method further includes transmitting from the service unit upstream telephony information and control data modulated on orthogonal carriers in a second frequency bandwidth over the distribution network. In addition, the method includes adjusting at least one local transmission characteristic when an adjustment command from a head end terminal is received in the downstream control data. The downstream control data is based on prior upstream transmissions from the service unit.

Claims

1. A distributed loop method for a multi-point to point communication system, the communication system having a plurality of orthogonal carriers in a first frequency bandwidth for downstream transmission from a head end to a plurality of remote units and a plurality of carriers orthogonal at the head end in a second frequency bandwidth for upstream transmission from the plurality of remote units to the head end, each plurality of orthogonal carriers having at least one control channel associated therewith, the method comprising:

detecting symbol timing at the head end of data transmitted upstream from at least one of the remote units;

generating at the head end a symbol timing adjustment command based on the detected symbol timing;

transmitting the symbol timing adjustment command to the at least one remote unit over the at least one control channel associated with the plurality of orthogonal carriers in the first frequency bandwidth; and

adjusting symbol timing at the remote unit as a function of the symbol timing adjustment command.

2. The method according to claim 1, wherein the method further comprises:

detecting carrier frequency at the head end transmitted from at least one of the remote units;

generating at the head end a carrier frequency adjustment command based on the detected carrier frequency;

transmitting the carrier frequency adjustment command to the at least one remote unit over the at least one control channel associated with the plurality of orthogonal carriers in the first frequency bandwidth; and

adjusting carrier frequency as a function of the carrier frequency adjustment command.

3. The method according to claim 2, wherein adjusting symbol timing at the remote unit as a function of the symbol timing adjustment command and adjusting carrier frequency as a function of the carrier frequency adjustment command are repeated until symbols transmitted upstream from the plurality of remote units arrive simultaneously at the head end and the plurality of orthogonal carriers utilized for such upstream transmission are aligned orthogonally.

4. The method according to claim 1, wherein adjusting adjusting symbol timing at the remote unit as a function of the symbol timing adjustment command is repeated until symbols transmitted upstream from the plurality of remote units arrive simultaneously at the head end.

5. The method according to claim 1, wherein the method further includes:

detecting transmission amplitude at the head end of data transmitted upstream from at least one of the remote units;

generating at the head end an amplitude adjustment command based on the detected transmission amplitude;

transmitting the amplitude adjustment command to be the at least one remote unit over the at least one control channel associated with the plurality of orthogonal carriers in the first frequency bandwidth; and

adjusting transmission amplitude of upstream transmission at the remote unit as a function of the amplitude adjustment command.

6. A method of distributed loop control, the method comprising:

receiving at a head end terminal upstream telephony and control data in a first frequency bandwidth over a distribution network;

demodulating the upstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in the first frequency bandwidth;

detecting at least one local transmission characteristic of at least the telephony data transmitted upstream from at least one remote unit, wherein the at least one local transmission characteristic comprises one or more of symbol timing, transmission frequency, amplitude of transmission and carrier frequency;

generating an adjustment command as a function of the at least one local transmission characteristic;

modulating downstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in a second frequency bandwidth; and

transmitting the adjustment command to a service unit associated with the at least one remote unit in the downstream control data;

wherein detecting at least one local transmission characteristic of data transmitted upstream comprises detecting symbol timing of data transmitted upstream;

wherein detecting symbol timing of data transmitted upstream comprises detecting symbol timing in response to a command from a head end controller;

generating a symbol timing error;

generating a symbol timing adjustment command based on the symbol timing error; and

transmitting the symbol timing adjustment command to a service unit associated with the at least one remote unit in the downstream control data.

7. A method of distributed loop control, the method comprising:

receiving at a head end terminal upstream telephony and control data in a first frequency bandwidth over a distribution network;

demodulating the upstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in the first frequency bandwidth;

detecting at least one local transmission characteristic of at least the telephony data transmitted upstream from at least one remote unit, wherein the at least one local transmission characteristic comprises one or more of symbol timing, transmission frequency, amplitude of transmission and carrier frequency;

generating an adjustment command as a function of the at least one local transmission characteristic;

modulating downstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in a second frequency bandwidth; and

transmitting the adjustment command to a service unit associated with the at least one remote unit in the downstream control data;

wherein detecting at least one local transmission characteristic comprises detecting the transmission frequency of a service unit associated with the at least one remote unit;

wherein detecting the transmission frequency of the service unit comprises detecting the transmission frequency of the service unit in response to a command from a head end controller of the head end terminal;

generating a transmission frequency error;

generating a transmission frequency adjustment command based on the transmission frequency error; and

transmitting the transmission frequency adjustment command to a service unit associated with the at least one remote unit in the downstream control data.

8. A method of distributed loop control, the method comprising:

receiving at a head end terminal upstream telephony and control data in a first frequency bandwidth over a distribution network;

demodulating the upstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in the first frequency bandwidth;

detecting at least one local transmission characteristic of at least the telephony data transmitted upstream from at least one remote unit, wherein the at least one local transmission characteristic comprises one or more of symbol timing, transmission frequency, amplitude of transmission and carrier frequency;

generating an adjustment command as a function of the at least one local transmission characteristic;

modulating downstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in a second frequency bandwidth; and

transmitting the adjustment command to a service unit associated with the at least one remote unit in the downstream control data; and

wherein detecting at least one local transmission characteristic comprises detecting the amplitude of transmission by a service unit associated with the at least one remote unit.

9. A method of distributed loop control, the method comprising:

receiving at a head end terminal upstream telephony and control data in a first frequency bandwidth over a distribution network;

demodulating the upstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in the first frequency bandwidth;

detecting at least one local transmission characteristic of at least the telephony data transmitted upstream from at least one remote unit, wherein the at least one local transmission characteristic comprises one or more of symbol timing, transmission frequency, amplitude of transmission and carrier frequency;

generating an adjustment command as a function of the at least one local transmission characteristic;

modulating downstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in a second frequency bandwidth; and

transmitting the adjustment command to a service unit associated with the at least one remote unit in the downstream control data;

wherein detecting at least one local transmission characteristic comprises detecting the amplitude of transmission by a service unit associated with the at least one remote unit; and

wherein detecting the amplitude of transmission by the service unit associated with the at least one remote unit comprises detecting the amplitude of transmission in response to a command from a head end controller of the head end terminal.

10. A method of distributed loop control, the method comprising:

receiving at a head end terminal upstream telephony and control data in a first frequency bandwidth over a distribution network;

demodulating the upstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in the first frequency bandwidth;

detecting at least one local transmission characteristic of at least the telephony data transmitted upstream from at least one remote unit, wherein the at least one local transmission characteristic comprises one or more of symbol timing, transmission frequency, amplitude of transmission and carrier frequency;

generating an adjustment command as a function of the at least one local transmission characteristic;

modulating downstream telephony and control data on a plurality of orthogonal carriers having at least one control channel associated therewith in a second frequency bandwidth; and

transmitting the adjustment command to a service unit associated with the at least one remote unit in the downstream control data;

wherein detecting at least one local transmission characteristic comprises detecting the amplitude of transmission by a service unit associated with the at least one remote unit;

wherein detecting the amplitude of transmission by the service unit associated with the at least one remote unit comprises detecting the amplitude of transmission in response to a command from a head end controller of the head end terminal;

generating an amplitude error;

generating an amplitude adjustment command based on the amplitude error; and

transmitting the amplitude adjustment command to the service unit associated with the at least one remote unit in the downstream control data.

11. A method of distributed loop control, the method comprising:

receiving at a service unit downstream control and telephony information modulated on orthogonal carriers in a first frequency bandwidth over a distribution network;

transmitting from the service unit upstream telephony information and control data modulated on orthogonal carriers in a second frequency bandwidth over the distribution network;

adjusting at least one local transmission characteristic when an adjustment command from a head end terminal is received in the downstream control data, wherein the downstream control data is based on prior upstream transmissions from the service unit, wherein the at least one local transmission characteristic comprises one or more of symbol timing, carrier frequency and transmission amplitude; and

wherein adjusting at least one local transmission characteristic comprises adjusting transmission amplitude of upstream transmission in response to an amplitude adjustment command.