Universal modem for digital video, audio and data communications

• US 6,192,070 B1
• Filed: 01/02/1998
• Issued: 02/20/2001
• Est. Priority Date: 01/02/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Mizutani, Yoshiki, Nakayama, Hiroyuki, Bao, Jay, Poon, Tommy C.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): DEPPE, BETSY LEE
• Application Number:
  US09/002,438
• Time in Patent Office: 1,145 Days
• Field of Search: 375/222, 375/219, 375/259, 375/285, 375/324, 375/328, 375/346, 375/296, 375/284, 375/232, 375/377, 375/340, 455/501, 708/323, 332/185, 329/372
• US Class Current: 375/222
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0032 Without explicit signalling
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

A universal modem has a software-configurable modulator/demodulator which accommodates different modulation formats such as those associated with terrestrial, cable, phone line, satellite and wireless communications to be transmitted and received through a single device in which the modem has reconfigurable logic to accommodate the format of the signals being received or transmitted. In one embodiment, the system tracks channel noise and changes modulation format at both the transmit and receive sides of the system through the use of a controller that controls both sides.

Claims

1. In a network communications system in which information is transmitted from a send side to a receive side over a communications channel, an apparatus for improving system performance comprising:

means for sensing a channel parameter; and

means for changing a modulation format of the transmitted information by generating instructions including modulation format configuration data, responsive to the sensed channel parameter, and having software-configurable logic means for changing the modulation format in accordance with the instructions, wherein said software-configurable logic means includes logic elements whose functionality is capable of being changed in software.

2. The apparatus of claim 1, wherein said modulation format changing means includes:

a universal modem at each of said sides, each universal modem providing different modulation formats for use in the modulation and demodulation of a signal, the universal modem at the transmit side including a modulator and the universal modem at the receive side including a demodulator;

means for generating, as an output, configuration instructions for said software-configurable logic means;

means for coupling said output to said software configurable logic means to configure said modems for the modulation format specified by said configuration instructions; and

means responsive to the sensing of said channel parameter for causing said instruction generating means to change the modulation format generated by the universal modem at said send side and a demodulation format of the universal modem at said receive side to a changed format.

3. The apparatus of claim 2, wherein said detected parameter is channel noise, and wherein said changed format is one which minimizes the effects of channel noise.

4. The apparatus of claim 2, wherein said modulation format changing means includes:

means for generating a control signal for specifying modulation formats, each of said modems coupled to said control signal and providing respectively modulation and demodulation in accordance with the format specified by said control signal;

means for generating, as an output, different instructions for different modulation formats, each of said different instructions including modulation format configuration data based on the modulation format specified by said control signal;

a memory for storing said modulation format configuration data, said memory being coupled to an associated modem for supplying said modulation format configuration data thereto; and

means responsive to said instructions to configure the associated modem for one of said different modulation formats in accordance with the configuration data included therein.

5. In a network communications system in which information is transmitted from a send side to a receive side over a communications channel, an apparatus for improving system performance comprising:

means for sensing a channel parameter; and

means for changing a modulation format of the transmitted information by generating instructions including modulation format configuration data, responsive to the sensed channel parameter, wherein said modulation format changing means includes;

a universal modem at each of said sides, each universal modem providing different modulation formats for use in the modulation and demodulation of a signal, the universal modem at the transmit side including a modulator and the universal modem at the receive side including a demodulator, said modulator and demodulator each having software-configurable logic means for respectively providing modulation and demodulation of a signal;

means for generating, as an output, configuration instructions for said software-configurable logic means;

means for coupling said output to said software configurable logic means to configure said modems for the modulation format specified by said configuration instructions;

means responsive to the sensing of said channel parameter for causing said instruction generating means to change the modulation format generated by the universal modem at said send side and a demodulation format of the universal modem at said receive side to a changed format;

and wherein said software-configurable logic means includes a number of elements, each performing a different modulation/demodulation function, and means for interconnecting said elements to perform in accordance with said configuration instructions.

6. The apparatus of claim 5, wherein said elements are taken from a group consisting of arithmetic logic units, registers, fifo buffers, gates, finite impulse response filters and infinite impulse response filters.

7. A system for communicating over a network, comprising:

a first modem including a first memory configured to store information corresponding to multiple modulation formats and a modulation circuit which is reconfigurable to modulate signals in any of the multiple modulation formats in accordance with the information stored in the first memory;

a second modem including a second memory configured to store information corresponding to the multiple modulation formats and a demodulation circuit which is reconfigurable to demodulate signals in any of the multiple modulation formats in accordance with the stored in the second memory; and

a controller configured to direct changes in the information corresponding to the multiple modulation formats stored in the first and the second memories, such that the information stored in the first memory corresponds to the information in the second memory.

8. A system according to claim 7, wherein the controller is further configured to direct changes which include adding information corresponding to a new modulation format not previously included in the multiple modulation formats.

9. A system according to claim 7, wherein the modulation circuit is configured to modulate a first signal in a first of the multiple modulation formats and the demodulation circuit is configured to demodulate the first signal in the first modulation format, and further comprising:

a noise detector configured to detect noise in the first signal;

wherein, if the detected noise exceeds a threshold, the controller is further configured to direct the first modem to reconfigure the modulation circuit to modulate a subsequent signal in a second of the multiple modulation formats, which is different than the first modulation format, and to direct the second modem to reconfigure the demodulation circuit to demodulate the subsequent signal in the second modulation format.

10. A system according to claim 7, wherein the information includes at least one of frequency information and bandwidth information associated with each of the multiple modulation formats.

11. A method for communicating over a network, comprising:

storing information corresponding to multiple modulation formats in a first memory;

configuring a modulation circuit in accordance with the information stored in the first memory to modulate signals in any of the multiple modulation formats;

storing information corresponding to the multiple modulation formats in a second memory;

configuring a demodulation circuit in accordance with the information stored in the second memory to demodulate signals in any of the multiple modulation formats; and

directing changes in the information corresponding to the multiple modulation formats stored in the first and the second memories, such that the information stored in the first memory corresponds to the information in the second memory.

12. A method according to claim 11, wherein the directed changes include directing additional information corresponding to a new modulation format not previously included in the multiple modulation formats to be stored in the first memory and the second memory.

13. A method according to claim 11, wherein the modulation circuit is configured to modulate a first signal in a first of the multiple modulation formats and the demodulation circuit is configured to demodulate the signal in the first modulation format, and further comprising the steps of:

detecting noise in the first signal;

determining if the detected noise exceeds a threshold;

reconfiguring the modulation circuit in accordance with the information stored in the first memory to modulate a subsequent signal in a second of the multiple modulation formats, which is different than the first modulation format, if the detected noise is determined to exceed the threshold; and

reconfiguring the demodulation circuit in accordance with the information stored in the second memory to demodulate the subsequent signal in the second modulation format, if the detected noise is determined to exceed the threshold.

14. An apparatus for communicating over a network, comprising:

a demodulation circuit which is reconfigurable so as to correspond to any of multiple modulation formats and capable of receiving a signal having a data portion which is modulated in any one of the multiple modulation formats and a header portion which is modulated in only a single of the multiple modulation formats and identifies the data portion modulation format, wherein said demodulation circuit includes a number of software-reconfigurable logic elements for changing the modulation format; and

a controller capable of directing the configuration of the demodulation circuit to correspond to the header portion modulation format in order for the header portion to be demodulated and the data portion modulation format to thereby be determined, and of directing the reconfiguration of the demodulation circuit to correspond to the determined data portion modulation format in order for the data portion to be demodulated and the data to thereby be determined.

15. An apparatus according to claim 14, wherein the multiple modulation formats include at least three modulation formats.

16. An apparatus according to claim 14, further comprising:

a memory configured to store information associated with each of the multiple modulation formats;

wherein the controller is further capable of directing the configuration of the demodulation circuit to correspond to the header portion modulation format in accordance with the stored information associated with the header portion modulation format and of directing the reconfiguration of the demodulation circuit to correspond to the determined data portion modulation format in accordance with the stored information associated with the data portion modulation format.

17. An apparatus for communicating over a network, comprising:

a modulation circuit which is reconfigurable so as to correspond to any of multiple modulation formats and capable of generating a signal having a data portion which is modulated in a first of the multiple modulation formats and a header portion which is modulated in a second of the multiple modulation formats, different than the first modulation format, and identifies the first modulation format, wherein said modulation circuit includes a number of software-reconfigurable logic elements for changing the modulation format; and

a controller capable of directing the modulation circuit to be reconfigured to correspond to a first of the multiple modulation formats in order for a header portion of a signal to be modulated in the first modulation format and of directing the modulation circuit to be reconfigured to correspond to a second of the multiple modulation formats, different than the first modulation format in order for a data portion of a signal to be modulated in the second modulation format.

18. An apparatus according to claim 17, wherein the multiple modulation formats include at least three modulation formats.

19. An apparatus according to claim 17, further comprising:

a memory configured to store information associated with each of the multiple modulation formats;

wherein the controller is further capable of directing the reconfiguration of the modulation circuit to correspond to the first modulation format in accordance with the stored information associated with the first modulation format and the reconfiguration of the modulation circuit to correspond to the second modulation format in accordance with the stored information associated with the second modulation format.