RANGING AND ROUND TRIP DELAY TIMING ADJUSTMENT IN A MULTI-POINT TO POINT BIDIRECTIONAL COMMUNICATION SYSTEM

• US 20090080505A1
• Filed: 11/17/2008
• Published: 03/26/2009
• Est. Priority Date: 02/06/1995
• Status: Active Grant

• Current Assignee: HTC Corporation
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Geile, Michael J., Brede, Jeffrey
• Granted Patent: US 7,773,537 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• 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

Systems and methods for ranging adjustments are provided. In one embodiment, a remote service unit comprises: a transceiver communicatively coupled with a host in a multi-point to point configuration, the transceiver configured to communicate with the host via an OFDM waveform; and a multi-carrier modem coupled to the transceiver and configured to demodulate downstream information data from the OFDM waveform, the multi-carrier modem further configured to modulate upstream information data onto the OFDM waveform. The multi-carrier modem modulates upstream information data onto distinct subcarriers of the OFDM waveform, the multi-carrier modem synchronized with the host so that upstream OFDM signals transmitted by the transceiver and other upstream OFDM signals received at the host unit combine to a unified OFDM waveform. The multi-carrier modem adjusts a round trip path delay between the remote service unit and the host based on a path delay correction received from the host unit.

Claims

1. A host unit for a multi-point to point communication system, the host unit comprising:

a transceiver communicatively coupled with a plurality of remote units in a multi-point to point configuration, the transceiver configured to communicate with the plurality of remote units using orthogonal frequency division multiplexing (OFDM), wherein upstream OFDM signals from at least two of the plurality of remote units combine to a unified OFDM waveform of adjacent spectrally overlapping carriers at the host unit;

a multi-carrier modem coupled to the transceiver and configured to demodulate upstream information from the unified OFDM waveform based on a Fourier transform algorithm, the multi-carrier modem further configured to modulate downstream information data onto a downstream OFDM waveform based on an inverse Fourier transform algorithm;

wherein the multi-carrier modem is further configured to estimate an overall path delay correction based on at least one tone of the orthogonal frequency division multiplexing waveform transmitted by a first remote unit of the plurality of remote units; and

wherein the transceiver is further configured to transmit the overall path delay correction to the first remote unit.

2. The host unit of claim 1, wherein the multi-carrier modem is further configured to adjust a round trip path delay associated with the first remote unit.

3. The host unit of claim 1, wherein the multi-carrier modem is further configured to adjust at least one characteristic of the plurality of tones such that when OFDM waveforms are transmitted from the first remote unit and at least one other remote unit of the plurality of remote units, the orthogonality of the unfired OFDM waveform when received at the host unit is improved.

4. The host unit of claim 5, wherein the multi-carrier modem is configured to adjust at least one of a carrier frequency, a carrier amplitude, and a timing.

5. The host unit of claim 2, wherein the plurality of tones are received concurrently from at least two of the plurality of remote units.

6. The host unit of claim 1, the transceiver communicatively coupled with the plurality of remote units by a distribution network.

7. The host unit of claim 6, wherein the distribution network comprises one of a wireless system and a hybrid fiber/coax network.

8. A remote service unit for a multi-point to point communication system, the remote service unit comprising:

a transceiver communicatively coupled with a host unit in a multi-point to point configuration, the transceiver configured to communicate with the host unit via an orthogonal frequency division multiplexing waveform;

a multi-carrier modem coupled to the transceiver and configured to demodulate downstream information data from the orthogonal frequency division multiplexing waveform, the multi-carrier modem further configured to modulate upstream information data onto the orthogonal frequency division multiplexing waveform;

wherein the multi-carrier modem modulates upstream information data onto distinct subcarriers of the orthogonal frequency division multiplexing waveform, the multi-carrier modem synchronized with the host unit such that upstream orthogonal frequency division multiplexing signals transmitted by the transceiver and other upstream orthogonal frequency division multiplexing signals received at the host unit combine to a unified orthogonal frequency division multiplexing waveform of adjacent spectrally overlapping carriers at the host unit;

wherein the multi-carrier modem is configured to adjust a round trip path delay between the remote service unit and the host unit based on a path delay correction received from the host unit.

9. The remote service unit of claim 8, wherein the modulator is configured to adjust at least one of a carrier frequency, a carrier amplitude, and a timing of the upstream orthogonal frequency division multiplexing signals transmitted by the transceiver.

10. The remote service unit of claim 8, the transceiver communicatively coupled with the host unit by a distribution network.

11. The remote service unit of claim 11, wherein the distribution network comprises one of a wireless system and a hybrid fiber/coax network.

12. A bi-directional communication system, the system comprising:

a plurality of remote units;

a multipoint-to-point host unit communicatively coupled with the plurality of remote units in a multi-point to point configuration, the multipoint-to-point host unit including a multi-carrier modem configured to communicate with the plurality of remote units using orthogonal frequency division multiplexing (OFDM), wherein upstream OFDM signals from at least two of the plurality of remote units combine to a unified OFDM waveform of adjacent spectrally overlapping carriers at the host unit;

wherein the multipoint-to-point host unit is configured to estimate a round trip path delay correction associated with at least one of the plurality of remote units; and

wherein the multipoint-to-point host unit is configured to adjust the round trip path delay associated with the at least one of the plurality of remote units.

13. The system of claim 12, wherein the at least one of the plurality of remote units is configured to adjust a round trip path delay based on the round trip path delay correction estimated by the host unit.

14. The system of claim 12, the plurality of remote units each including a modulator for modulating up to a plurality of tones with upstream information using orthogonal frequency division multiplexing, wherein the modulator is configured to adjust at least one characteristic of the plurality of tones such that when OFDM waveforms are transmitted from the first remote unit and at least one other remote unit of the plurality of remote units, the orthogonality of the unified OFDM waveform when received at the host unit is improved.

15. The system of claim 12, wherein the modulator is configured to adjust at least one of a carrier frequency, a carrier amplitude, and a timing.

16. The system of claim 14, wherein the plurality of tones are received concurrently from at least two of the plurality of remote units.

17. The system of claim 12, further comprising a distribution network coupled between the multipoint-to-point host unit and the plurality of remote units.

18. The system of claim 17, wherein the distribution network comprises one of a wireless system and a hybrid fiber/coax network.