Systems and method for orthogonal frequency divisional multiplexing

• US 7,995,454 B2
• Filed: 10/29/2007
• Issued: 08/09/2011
• Est. Priority Date: 02/06/1995
• Status: Expired due to Fees

• Current Assignee: HTC Corporation
• Original Assignee: HTC Corporation
• Inventors: Geile, Michael J., Roberts, Harold A., Anderson, Brian D., Brede, Jeffrey, Fort, Michael J., Ferris, Tammy
• Primary Examiner(s): Jain, Raj K
• Application Number:
  US11/927,397
• Publication Number:
  US 20080225690A1
• Time in Patent Office: 1,380 Days
• Field of Search: None
• US Class Current: 370/206
• 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 orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising spectrally overlapping carrier signals from at least two of a plurality of remotes, wherein the spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to calculate an elapsed time for each of the two remotes, the elapsed time representing a time between transmitting a ranging signal to a remote and receiving a signal from the remote in response to the ranging signal; the controller further programmed to reducing any difference between at least two elapsed times by instructing at least one of the plurality of remotes to adjust a delay.

Claims

1. A method for quality based assessments of orthogonal channels for remote service units of an OFDM based multiple access system, the method comprising:

monitoring a first subset of orthogonal carriers within an OFDM waveform associated with at least one communication channel, wherein the first subset of orthogonal carriers comprises less than all of the orthogonal carriers within the OFDM waveform;

monitoring a second subset of orthogonal carriers within the OFDM waveform associated with at least one communication channel, wherein the second subset of orthogonal carriers includes different orthogonal carriers than the first subset of orthogonal carriers;

determining a first quality measurement for the first subset of orthogonal carriers;

determining a second quality measurement for the second subset of orthogonal carriers;

communicating a notification message regarding the quality measurements for the first subset of orthogonal carriers and the second subset of orthogonal carriers; and

adjusting a frequency of upstream carriers of the OFDM waveform to maintain orthogonality within the OFDM waveform.

2. The method of claim 1, further comprising:

maintaining quality statistics for the first subset of orthogonal carriers in a memory.

3. The method of claim 2, wherein the quality statistics include either a bit error rate or a signal-to-noise ratio.

4. The method of claim 1, further wherein the first subset of orthogonal carriers comprises more than one orthogonal carrier.

5. The method of claim 1, wherein the quality information includes a quality statistic.

6. The method of claim 1, further comprising:

communicating data over the at least one communication channel based on whether the quality measurement for the first subset of orthogonal carriers satisfies a quality standard.

7. The method of claim 1, wherein the first subset of orthogonal carriers are contiguous sets of orthogonal carriers within the OFDM waveform.

8. The method of claim 1, further comprising:

comparing the quality measurement for the second subset of orthogonal carriers against predetermined quality standards.

9. The method of claim 1, further comprising determining when the quality measurements for the first subset of orthogonal carriers exceeds allowable limits.

10. The method of claim 1, wherein the second subset of orthogonal carriers comprises less than all of the orthogonal carriers within the OFDM waveform.

11. The method of claim 1 further comprising adjusting a timing of upstream carriers of the OFDM waveform so that carriers from a plurality of remote units combine into a unified OFDM waveform at a host unit.

12. A method for quality based assessments of orthogonal channels for remote service units of an OFDM based multiple access system, the method comprising:

monitoring a first subset of orthogonal carriers within an OFDM waveform associated with at least one communication channel, wherein the first subset of orthogonal carriers comprises less than all of the orthogonal carriers within the OFDM waveform;

monitoring a second subset of orthogonal carriers within the OFDM waveform associated with at least one communication channel, wherein the second subset of orthogonal carriers comprises at least one orthogonal carrier not included in the first subset of orthogonal carriers;

determining a first quality measurement for the first subset of orthogonal carriers;

determining a second quality measurement for the second subset of orthogonal carriers;

communicating a notification message to an OFDM carrier allocator in a host unit regarding the quality measurements for the first subset of orthogonal carriers and the second subset of orthogonal carriers;

receiving at a remote service unit via an OFDM waveform an allocation of orthogonal carriers, the allocation based at least in part on at least one of the first and second quality measurements; and

adjusting a frequency of upstream carriers of the OFDM waveform to maintain orthogonality within the OFDM waveform.

13. The method of claim 12, further comprising:

maintaining quality statistics for the first subset of orthogonal carriers in a memory.

14. The method of claim 13, wherein the quality statistics include either a bit error rate or a signal-to-noise ratio.

15. The method of claim 12, further wherein the first subset of orthogonal carriers comprises more than one orthogonal carrier.

16. The method of claim 12, wherein the quality information includes a quality statistic.

17. The method of claim 12, further comprising:

communicating data over the at least one communication channel based on whether the quality measurement for the first subset of orthogonal carriers satisfies a quality standard.

18. The method of claim 12, wherein the first subset of orthogonal carriers are contiguous sets of orthogonal carriers within the OFDM waveform.

19. The method of claim 12, further comprising:

comparing the quality measurement for the second subset of orthogonal carriers against predetermined quality standards.

20. The method of claim 12, further comprising

determining when the quality measurements for the first subset of orthogonal carriers exceeds allowable limits.

21. The method of claim 12, further comprising wherein the second subset of orthogonal carriers comprises less than all of the orthogonal carriers within the OFDM waveform.

22. The method of claim 12 further comprising adjusting a timing of upstream carriers from the remote unit so that the upstream carriers from the remote unit combine with carriers from at least one other remote unit into a unified OFDM waveform at a host unit.

23. The method of claim 12, wherein the allocation of orthogonal carriers is an allocation of upstream orthogonal carriers for communication from the remote service unit to the host unit.