Synchronization in a communications system with multicarrier telephony transport

• US 6,336,201 B1
• Filed: 09/15/1999
• Issued: 01/01/2002
• Est. Priority Date: 09/26/1994
• Status: Expired due to Term

• Current Assignee: HTC Corporation
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Geile, Michael J., Brede, Jeffrey, Buska, Steven P., Smigelski, Thomas
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US09/396,847
• Time in Patent Office: 839 Days
• Field of Search: 709/234, 379/93.14, 379/93.09, 370/545, 370/401, 375/371, 455/3.1, 395/552, 714/755
• US Class Current: 714/755
• 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 staggering the arrival of frames of data at a head end in a communication system. The method includes receiving at a first service unit upstream telephony data is described. The telephony data includes a first payload message. The method includes receiving at a second service unit upstream telephony data, wherein the telephony data includes a second payload message. The method further includes formatting the first payload message at the first service unit as a first sequence of frames and formatting the second payload message at the second service unit as a second sequence of frames. In addition, the method includes transmitting the first sequence of frames on a first carrier so as to arrive at the head end at a first time and transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time.

Claims

1. In a communications system for transmitting payload messages between a central head end and a plurality of remote units over a plurality of coherent carriers within messages each having a sequence of frames, a method for decreasing peak decoding load at said head end, comprising:

formatting at least first and second ones of said messages as first and second sequences of frames in first and second ones of said remote units, wherein each of the first and second sequences of frames includes at least one check-symbol frame;

transmitting said first message over a first of said carriers from said first remote unit to said head end beginning at a first time;

transmitting said second message over a second of said carriers from said second remote unit to said head end beginning at a second time, wherein the first and second sequences of frames arrive at the head end such that the at least one check-symbol frame of the first sequence of frames is not aligned with the at least one check-symbol frame of the second sequence of frames;

decoding said first message at a third time in a processor located in said head end; and

decoding said second message at a fourth time in the same processor in said head end.

2. The method of claim 1, wherein said first and second messages have first and second different numbers of frames.

3. The method of claim 2, wherein the difference between the starting times of said first and second messages is different for each of said different message lengths.

4. The method of claim 1, wherein said head end transmits a superframe signal to said remote units, and wherein each of said first and second times is an offset from said superframe signal.

5. A method of staggering the arrival of frames of data at a head end in a communication system, the method comprising:

receiving at a first service unit upstream telephony data, wherein the telephony data includes a first payload message;

receiving at a second service unit upstream telephony data, wherein the telephony data includes a second payload message;

formatting the first payload message at the first service unit as a first sequence of frames that includes at least one check-symbol frame;

formatting the second payload message at the second service unit as a second sequence of frames that includes at least one check-symbol frame;

transmitting the first sequence of frames on a first carrier so as to arrive at the head end at a first time; and

transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the first and second sequences of frames arrive at the head end such that the at least one check-symbol frame of the first sequence of frames is not aligned with the at least one check-symbol frame of the second sequence of frames.

6. The method of claim 5, wherein transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time comprises transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the second time begins after the arrival of the first message at the head end.

7. The method of claim 5, wherein transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time comprises transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the second time begins after the end of the transmission of the first message.

8. The method of claim 5, wherein transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time comprises transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the second sequence of frames has a different number of frames than the first sequence of frames.

9. The method of claim 5, wherein transmitting a first sequence of frames and transmitting a second sequence of frames comprises transmitting a first sequence of frames and transmitting a second sequence of frames wherein the first sequence of frames is within a first subband of channels and the second sequence of frames is within a second subband of channels.

10. A method of staggering the arrival of frames of data at a head end in a communication system, the method comprising:

receiving at a first service unit upstream telephony data, wherein the telephony data includes a first payload message;

receiving at a second service unit upstream telephony data, wherein the telephony data includes a second payload message;

formatting the first payload message at the first service unit as a first sequence of frames that includes at least one check-symbol frame;

formatting the second payload message at the second service unit as a second sequence of frames that includes at least one check-symbol frame;

transmitting the first sequence of frames on a first carrier so as to arrive at the head end at a first time;

transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the first and second sequences of frames arrive at the head end such that the at least one check-symbol frame of the first sequence of frames is not aligned with the at least one check-symbol frame of the second sequence of frames; and

decoding, at the head end, the first sequence of frames at a third time and the second sequence of frames at a fourth time.

11. The method of claim 10, wherein transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time comprises transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the second time begins after the arrival of the first message at the head end.

12. The method of claim 10, wherein transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time comprises transmitting the second sequence of frames on a second carrier so as to arrive at the bead end at a second time, wherein the second time begins after the end of the transmission of the first message.

13. The method of claim 10, wherein transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time comprises transmitting the second sequence of frames on a second carrier so as to arrive at the head end at a second time, wherein the second sequence of frames has a different number of frames than the first sequence of frames.

14. The method of claim 10, wherein transmitting a first sequence of frames and transmitting a second sequence of frames comprises transmitting a first sequence of frames and transmitting a second sequence of frames wherein the first sequence of frames is within a first subband of channels and the second sequence of frames is within a second subband of channels.

15. A communication system, comprising:

a head end terminal;

a plurality of service units;

a distribution network having a plurality of coherent carriers coupled between the head end terminal and the plurality of service units;

wherein a first service unit of the plurality of service units receives a plurality of messages, formats a payload message of one of the plurality of messages as a first sequence of frames that includes at least one check-symbol frame, and transmits the first sequence of frames on a first carrier to the head end terminal at a first time; and

wherein a second service unit of the plurality of service units receives a plurality of messages, formats a payload message of one of the plurality of messages as a second sequence of frames that includes at least one check-symbol frame, and transmits the second sequence of frames on a second carrier to the head end terminal at a second time, wherein the first and second sequences of frames arrive at the head end such that the at least one check-symbol frame of the first sequence of frames is not aligned with the at least one check-symbol frame of the second sequence of frames.

16. The system of claim 15, wherein the second time begins after the end of the transmission of the first sequence of frames.

17. The system of claim 15, wherein the second time begins N frames past the first time.

18. The system of claim 15, wherein the second sequence of frames has a different number of frames than the first sequence of frames.

19. The system of claim 15, wherein the first sequence of frames is within a first subband of channels and the second sequence of frames is within a second subband of channels.

20. A communication system, comprising:

a head end terminal;

a plurality of service units;

a distribution network having a plurality of coherent carriers coupled between the head end terminal and the plurality of service units;

wherein a first service unit of the plurality of service units receives a plurality of messages, formats a payload message of one of the plurality of messages as a first sequence of frames that includes at least one check-symbol frame, and transmits the first sequence of frames on a first carrier to the head end terminal at a first time;

wherein a second service unit of the plurality of service units receives a plurality of messages, formats a payload message of one of the plurality of messages as a second sequence of frames that includes at least one check-symbol frame, and transmits the second sequence of frames on a second carrier to the head end terminal at a second time, wherein the first and second sequences of frames arrive at the head end such that the at least one check-symbol frame of the first sequence of frames is not aligned with the at least one check-symbol frame of the second sequence of frames; and

wherein the head end terminal includes a processor that decodes the first and second sequence of frames.

21. The system of claim 20, wherein the second time begins after the end of the transmission of the first sequence of frames.

22. The system of claim 20, wherein the second time begins N frames past the first time.

23. The system of claim 20, wherein the second sequence of frames has a different number of frames than the first sequence of frames.

24. The method of claim 20, wherein the first sequence of frames is within a first subband of channels and the second sequence of frames is within a second subband of channels.