Asymmetrical transport of data

• US 7,002,898 B1
• Filed: 07/31/2000
• Issued: 02/21/2006
• Est. Priority Date: 05/20/1996
• Status: Expired due to Fees

• Current Assignee: HTC Corporation
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Lou, Heng
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): SHAH, CHIRAG G
• Application Number:
  US09/629,782
• Time in Patent Office: 2,031 Days
• Field of Search: 370/352, 370/353, 370/354, 370/355, 370/356, 370/400, 370/203, 370/204, 370/206, 370/208, 375/242, 375/298, 375/353, 375/354
• US Class Current: 370/204
• 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 system is described which provides bidirectional transport of data at different data rates for each direction over a shared medium. In one embodiment, the different data rates are accomplished using different modulation techniques. For example, in the downstream direction, quadrature amplitude modulation (QAM) 64 is used and in the upstream direction orthogonal frequency division multiplexing (OFDM) is used. The QAM 64 modulation provides for a higher number of bits per hertz in a transmission channel. By using QAM 64 modulation, down stream transmission rates on the order of 30 megabits per second (Mbps) in a 6 MHz channel can be achieved. A number of 6 MHz channels can be combined to provide for even higher data rates.

Claims

1. A system for the asymmetrical transport of data over a network, the system comprising:

a data head end that is communicatively coupled to the network and to at least one data source;

at least one service unit coupled to the network;

an encoder that couples the data head end to the network, wherein the encoder modulates data from the at least one data source using a first modulation technique and transmits downstream the modulated data over the network in a first frequency band to selected service units, wherein the encoder is a quadrature amplitude modulation (QAM) encoder; and

each service unit including a decoder for demodulating data from the downstream transmission and a modulator that modulates data using orthogonal frequency division multiplexing (OFDM) for transmission upstream to the data head end over the same network in a second frequency band, such that the data rate of the downstream transmission is different from the data rate of the upstream transmission.

2. The system of claim 1, wherein the encoder is a quadrature amplitude modulation (QAM) 64 encoder.

3. The system of claim 1, wherein the data head end includes a full duplex 100 BaseT Ethernet connection to a switched Ethernet network.

4. The system of claim 1, wherein the data head end is coupled to the Internet.

5. The system of claim 1, and further comprising a telephony head end, coupled to the data head end and to the network, that transmits telephony data over the same network at a data rate different from the downstream transmission and that receives the upstream transmission for the data head end.

6. The system of claim 5, wherein the telephony head end includes a communication link with the data head end.

7. The system of claim 6, wherein the communication link includes at least one T1 or E1 communication link.

8. The system of claim 1, wherein the network is a hybrid fiber/coax network.

9. The system of claim 1, wherein the data rate of the downstream transmission is greater than the data rate of the upstream transmission.

17. The head end of claim 1, wherein the data rate of the downstream transmission is greater than the data rate of the upstream transmission.

10. A head end for an asymmetrical data transport network, the head end comprising:

a data head end having at least one interface for connection to a data source;

an encoder, communicatively coupled with the data source through the at least one interface of the data head end, wherein the encoder modulates data from the at least one data source using a first modulation technique and transmits downstream the modulated data over the network in a first frequency band to selected service units, wherein the encoder is a quadrature amplitude modulation (QAM) encoder; and

a telephony head end that receives data from service units for the data head end, wherein the data from the service units is modulated using orthogonal frequency division multiplexing (OFDM) for transmission upstream over the same network in a second frequency band, such that the data rate of the downstream transmission is different from the data rate of the upstream transmission.

11. The head end of claim 10, wherein the encoder is a quadrature amplitude modulation (QAM) 64 encoder.

12. The head end of claim 10, wherein the at least one interface of the data head end includes a full duplex 100 BaseT Ethernet connection to a switched Ethernet network.

13. The head end of claim 10, wherein the data head end is coupled to the Internet.

14. The head end of claim 10, and further comprising a communication link between the telephony head end and the data head end.

15. The head end of claim 14, wherein the communication link includes at least one T1 or E1 communication link.

16. The head end of claim 10, wherein the network is a hybrid fiber/coax network.

18. A method for transporting data over a network, the method comprising:

receiving downstream direction data at a head end from a data source;

modulating the downstream direction data from the data source with a quadrature amplitude modulation (QAM) modulation technique that produces a downstream transmission with a first data rate;

transmitting the downstream transmission over a network to a service unit;

receiving the downstream transmission at the service unit;

modulating data from the service unit with a modulation technique that produces an orthogonal frequency division multiplexing (OFDM) upstream transmission with a second data rate;

transmitting the upstream transmission over the network to the head end; and

receiving the upstream transmission from the service unit with a second, different data rate over the same network.

19. The method of claim 18, wherein modulating the downstream direction data comprises modulating the downstream direction data with a quadrature amplitude modulation (QAM) 64 modulation.

20. The method of claim 18, wherein receiving downstream direction data from a data source comprises receiving data from the Internet.

21. The method of claim 18, wherein modulating the downstream direction data comprises modulating the downstream direction data for transmission in at least one 6 MHz channel using quadrature amplitude modulation.

22. A service unit for asymmetrical transport of data over a network, the service unit comprising:

a decoder that receives downstream data in a first frequency band over the network with a first data rate wherein, the decoder is a quadrature amplitude modulation (QAM) decoder; and

a modulator, coupled to the same network, that provides upstream data over the network in a second, different frequency band with a second, different data rate using orthogonal frequency division multiplexing (OFDM).

23. The service unit of claim 22, wherein the decoder comprises a quadrature amplitude modulation (QAM) 64 decoder.

24. The service unit of claim 22, wherein the modulator provides upstream data with a data rate that is less than the data rate of the downstream data.