Ranging and round trip delay timing adjustment in a multi-point to point bidirectional communication system

• US 7,539,126 B2
• Filed: 03/15/2007
• Issued: 05/26/2009
• Est. Priority Date: 02/06/1995
• Status: Expired due to Fees

• Current Assignee: HTC Corporation
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Geile, Michael J., Brede, Jeffrey
• Primary Examiner(s): Jagannathan, Melanie
• Application Number:
  US11/686,888
• Publication Number:
  US 20070147229A1
• Time in Patent Office: 803 Days
• Field of Search: None
• US Class Current: 370/208
• 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 method for an orthogonal frequency division multiplexing multipoint-to-point communications system comprises establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration using orthogonal frequency division multiplexing; and adjusting a round trip path delay associated with the first remote unit.

Claims

1. A method for an orthogonal frequency division multiplexing (OFDM) multipoint-to-point communications system, the method comprising:

transmitting up to a plurality of tones from a first remote unit of a plurality of remote units to a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration using orthogonal frequency division multiple access, wherein the up to a plurality of tones from the first remote unit are configured to combine with at least one tone from at least one tone from at least one other remote unit of the plurality of remote units to a unified OFDM waveform of adjacent spectrally overlapping carriers at the host unit; and

adjusting a round trip path delay associated with the first remote unit.

2. The method of claim 1 further comprising:

adjusting at least one characteristic of the up to a plurality of tones such that when the up to a plurality of tones combine with the at least one tone from at least one other remote unit, the orthogonality of the unified OFDM waveform tones when received at the host unit is improved.

3. The method of claim 2, wherein adjusting at least one characteristic of the up to a plurality of tones comprises adjusting at least one of a carrier frequency, a carrier amplitude, and a phase.

4. The method of claim 1 further comprising:

receiving up to a plurality of tones from the first remote unit, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing; and

adjusting at least one characteristic of the plurality of tones such that when any tones are transmitted from the first remote unit and at least one other remote unit of the plurality of remote units, the orthogonality of the tones when received at the host unit is improved.

5. The method of claim 4, wherein adjusting at least one characteristic of

the plurality of tones comprises adjusting at least one of a carrier frequency, a carrier amplitude, and a phase.

6. The method of claim 1 further comprising:

sending a first signal on at least a first tone of the plurality of tones, the first signal

instructing the first remote unit to transmit a second signal onto at least a second tone of the plurality of tones;

estimating a round trip delay associated with the first remote unit based on the second signal; and

sending a third signal instructing the first remote unit to adjust transmission of data based on the estimated round trip delay.

7. The method of claim 1 further comprising:

estimating a round trip path delay time for the first remote unit that will align multiframes received at the host unit from the first remote unit with any other multiframes received at the host unit from the plurality of remote units.

8. The method of claim 1 further comprising:

receiving a ranging signal at the host unit, the ranging signal transmitted from the first remote unit;

estimating a round trip path delay based on the ranging signal; and

sending a path delay adjustment value to the first remote unit to assist in achieving orthogonal frequency division multiplexing for subsequent transmissions from the plurality of remote units to the host unit.

9. A method for an orthogonal frequency division multiplexing (OFDM) multipoint-to-point communications system, the method comprising:

receiving an orthogonal frequency division multiple access waveform at a multipoint-to-point host unit, the orthogonal frequency division multiple access waveform comprising a plurality of tones transmitted by a plurality of remote units, wherein adjacent spectrally overlapping carriers from at least two of the plurality of remote units combine to form a unified OFDM waveform at the host unit;

receiving at least one ranging signal at the multipoint-to-point host unit, the at least one ranging signal transmitted from at least one of the plurality of remote units;

estimating at least one round trip path delay based on the at least one ranging signal; and

adjusting the at least one round trip path delay between the multipoint-to-point host unit and the at least one of the plurality of remote units.

10. The method of claim 9, wherein adjusting the at least one round trip path delay further comprises adjusting each of the plurality of remote units to achieve alignment within a predefined margin at the host unit of any upstream transmissions by the plurality of remote units.

11. A method for an orthogonal frequency division multiplexing (OFDM) multipoint-to-point communications system, the method comprising:

transmitting at least one tone from a first remote unit of a plurality of remote units to a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration using orthogonal frequency division multiple access, wherein the at least one tone from the first remote unit is configured to combine with at least one tone from at least one other remote unit of the plurality of remote units to a unified OFDM waveform of adjacent spectrally overlapping carriers at the host unit;

receiving a round trip delay adjustment based on an estimated round trip delay period between the first remote unit and the host unit; and

delaying transmission of up to a plurality of tones from the first remote unit based on the round trip delay adjustment, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing.

12. The method of claim 11 further comprising:

receiving up to a plurality of tones from the host unit; and

receiving an instruction to delay transmission based on an estimated round trip delay associated with the first remote unit.

13. The method of claim 11 further comprising:

transmitting a ranging signal from the first remote unit to the host unit.