Method for adjusting power in a communication system with multicarrier telephony transport

• US 6,467,092 B1
• Filed: 09/16/1999
• Issued: 10/15/2002
• Est. Priority Date: 05/20/1996
• Status: Expired due to Term

• Current Assignee: HTC Corporation
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Solum, Jeff, Geile, Michael J., Roberts, Harold A., Fort, Michael J.
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US09/397,773
• Time in Patent Office: 1,125 Days
• Field of Search: 725/131, 725/107, 725/117, 725/124
• US Class Current: 725/131
• 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 transmitting data in a communication system is provided. The method includes adjusting upstream power levels in a multipoint-to-point communications system having a head end and a plurality of service units is provided. The method includes measuring power levels of signals from the service units at the head end and comparing the power levels with a nominal power level. Further, the method provides at least one coarse adjustment at the service units to correct for large variations between the measured power level nominal power level and at least one fine adjustment at the head end to correct for smaller variations between the measured power level and the nominal power level.

Claims

1. A method of adjusting upstream power levels in a bidirectional multipoint-to-point multichannel communications system having a single central head end and a plurality of service units located remotely from the head end and from each other, the method comprising:

repetitively scanning different channels associated with different ones of the remote service units;

in response to the scanning step, returning a predetermined signal from each of the remote service units to the head end;

measuring the received power level of each such signal against a nominal value;

for any remote unit whose received power level differs from the nominal value if the received power level has a first property, adjusting the received power level toward the nominal value at the head end by adjusting the coefficients of an equalizer at the head end; and

if the received power level has a second property, adjusting the transmitted power level at the corresponding remote unit so as to bring the received power level toward the nominal value, comprising;

sending a message from the head end to the corresponding remote unit; and

in response to the message, changing the power level of a transmitter located at the remote unit.

2. The method of claim 1, wherein the first property comprises the difference between the received power level and the nominal value being less than a certain amount.

3. The method of claim 1, wherein the second property comprises the difference between the received power level and the nominal value being greater than a certain amount.

4. The method of claim 1, further comprising time-smoothing the differences between the received power level and the nominal value before adjusting the received power level.

5. The method of claim 1, wherein the received and transmitted power levels are adjusted in steps.

6. The method of claim 5, wherein the steps in the transmitted power level are larger than those in the received power level.

7. The method of claim 5, wherein the steps in the transmitted power level are substantially less precise than those in the received power level.

8. The method of claim 1, and further comprising selecting one channel for each service unit to be scanned.

9. The method of claim 1, and further comprising if the received power level is substantially zero, loading default values in an equalizer at the head end.

10. The method of claim 1, wherein measuring the received power level of each such signal against a nominal value comprises measuring the received power level of each such signal against a previous value.

11. A method of adjusting upstream power levels in a multipoint-to-point communications system having a head end and a plurality of service units, the method comprising:

measuring power levels of signals from the service units at the head end;

comparing the power levels with a nominal power level;

providing at least one coarse adjustment at the service units to correct for large variations between the measured power level and the nominal power level, comprising;

sending a message from the head end to the corresponding remote unit; and

in response to the message, changing the power level of a transmitter located at the remote unit; and

providing at least one fine adjustment at the head end to correct for smaller variations between the measured power level and the nominal power level, wherein providing at least one fine adjustment comprises adjusting the coefficients of an equalizer at the head end.

12. The method of claim 11, wherein comparing power levels comprises comparing the measured power levels with a previous measured power level.

13. A method of adjusting upstream power levels in a multipoint-to-point multichannel communications system having a head end and a plurality of service units, the method comprising:

receiving a signal from each of the service units to the head end;

measuring the received power level of each such signal against a nominal value;

for any service unit whose received power level differs from the nominal value if the received power level has a first property, adjusting the received power level toward the nominal value at the head end by adjusting the coefficients of an equalizer at the head end; and

if the received power level has a second property, adjusting the transmitted power level at the corresponding service unit so as to bring the received power level toward the nominal value, comprising;

sending a message from the head end to the corresponding service unit; and

in response to the message, changing the power level of a transmitter located at the service unit.

14. The method of claim 13, wherein the first property comprises the difference between the received power level and the nominal value being less than a certain amount.

15. The method of claim 13, wherein the second property comprises the difference between the received power level and the nominal value being greater than a certain amount.

16. The method of claim 13, further comprising time-smoothing the differences between the received power level and the nominal value before adjusting the received power level.

17. The method of claim 13, wherein the received and transmitted power levels are adjusted in steps.

18. The method of claim 17, wherein the steps in the transmitted power level are larger than those in the received power level.

19. The method of claim 17, wherein the steps in the transmitted power level are substantially less precise than those in the received power level.