System for multi-frame alignment

• US 7,872,985 B2
• Filed: 11/17/2008
• Issued: 01/18/2011
• Est. Priority Date: 02/06/1995
• Status: Expired due to Fees

• Current Assignee: HTC Corporation
• Original Assignee: ADC DSL Systems, Inc. (TE Connectivity Ltd. (United Kingdom))
• Inventors: Geile, Michael J., Brede, Jeffrey
• Primary Examiner(s): Harper, Kevin C
• Application Number:
  US12/272,522
• Publication Number:
  US 20090074095A1
• Time in Patent Office: 792 Days
• Field of Search: 370/252, 370/343, 370/465, 370/480
• US Class Current: 370/252
• 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 bidirectional communication system is provided. In one embodiment, a system comprises a host and a plurality of remote units, wherein a plurality of tones is shared among the plurality of remote units in order to communicate with the host using orthogonal frequency division multiplexing, wherein the plurality of tones is shared in a manner that permits at least two of the remote units to transmit to the host at any one time using the plurality of tones. The host causes at least one remote unit to adjust a timing of symbols transmitted on at least one of the plurality of orthogonal tones in order to improve an alignment of multiframes received at the host.

Claims

1. An end-user communication device for a multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system, the end-user communication device comprising:

a remote unit that accesses a host unit using an orthogonal frequency division multiple access scheme wherein carriers transmitted by the remote unit overlap spectrally within an OFDM waveform with carriers simultaneously transmitted from at least one other remote unit that accesses the host unit via the OFDM waveform; and

wherein the host causes at least one remote unit to adjust a timing of symbols transmitted on at least one of the plurality of tones in order to improve an alignment of multiframes received at the host based on a predefined multiframe pattern.

2. The system of claim 1, wherein the host causes the at least one remote unit to adjust the timing of symbols transmitted on the at least one of the plurality of tones in order to align symbols of a first frame of the multiframes when received at the host.

3. The system of claim 1, wherein the host generates information indicative of a transmission adjustment for the at least one remote unit and communicates the information to the at least one remote unit for use by the at least one remote unit in making the transmission adjustment based at least in part on the information in order to improve the alignment of the multiframes when received at the host.

4. The system of claim 1, wherein the host generates information indicative of a transmission adjustment for the at least one remote unit and communicates the information to the at least one remote unit;

and

wherein the at least one remote unit adjusts a timing of a superframe clock signal based on the information.

5. The system of claim 1, wherein the host:

determines a phase shift associated with a receipt at the host of a first symbol transmitted from one of the plurality of remote units; and

causes the at least one remote unit to delay the transmission of a second symbol therefrom, wherein the delay is related to the phase shift.

6. The system of claim 1, wherein the host communicates at least one command to the at least one remote unit to synchronize upstream transmissions from the at least one remote unit, wherein the at least one remote unit adjusts the timing of symbols transmitted over the OFDM waveform, and a frequency of at least one OFDM carrier within the OFDM waveform, in response to the at least one command.

7. The system of claim 1, wherein the host causes the at least one remote unit to adjust a carrier amplitude of at least one OFDM carrier within the OFDM waveform.

8. The system of claim 1, wherein the system is used in a wireless network.

9. A system comprising:

a host; and

a plurality of remote units;

wherein the host simultaneously receives a plurality of upstream multiframes transmitted from at least two of the plurality of remote units on a plurality of spectrally overlapping tones within a shared orthogonal frequency division multiplexing waveform;

wherein a timing error for at least one remote unit is determined by the host; and

wherein at least one remote unit adjusts a manner in which symbols are transmitted therefrom based on the timing error to improve an alignment of multiframes received at the host.

10. The system of claim 9, wherein the grouping of frames is a multiframe.

11. The system of claim 9, wherein the at least one remote adjusts the manner in which symbols are transmitted therefrom in response to a timing adjustment command sent to the at least one remote, wherein the timing adjustment command is related to the timing error.

12. The system of claim 9, further comprising a distribution network coupled between the host and the plurality of remote units.

13. The system of claim 12, wherein the distribution network comprises a wireless system.

14. A host unit comprising:

a multipoint-to-point modem providing multiple access for a plurality of remote units using an orthogonal frequency division multiplexing (OFDM) waveform;

wherein the multipoint-to-point modem performs a fast fourier transform to demodulate signals from a plurality of spectrally overlapping tones in the OFDM waveform, wherein the OFDM waveform carries upstream information modulated onto the plurality of tones and organized into multiframes transmitted by at least two of the plurality of remote units; and

wherein the multipoint-to-point modem generates at least one command for at least one of the plurality of remote units to adjust a timing of symbols transmitted from the at least one of the plurality of remote units to the host unit to improve an alignment of the multiframes received at the host unit.

15. The host unit of claim 14, wherein the host generates the at least one command based on an alignment of symbols of a first frame of the multiframes received at the host.

16. The host unit of claim 14, wherein the multipoint-to-point modem generates a timing delay adjustment for the at least one remote unit.

17. The host unit of claim 14, wherein the multipoint-to-point modem generates the at least one command based on a signal received from the at least one of the plurality of remote units.

18. The host unit of claim 14, wherein the host unit communicates over a distribution network with the plurality of remote units.

19. The host unit of claim 14, wherein the host unit communicates over a wireless system with the plurality of remote units.

20. The system of claim 14, wherein the host generates the at least one command based on an alignment of symbols of a first frame of the multiframes received at the host.