Data transmission over amps networks

• US 5,911,115 A
• Filed: 03/31/1995
• Issued: 06/08/1999
• Est. Priority Date: 03/31/1995
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Nair, N. Gopolan, Brun, Zdenek
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Nguyen, Lee
• Application Number:
  US08/414,907
• Time in Patent Office: 1,530 Days
• Field of Search: 455/69, 455/43, 455/50.1, 455/63, 455/52.1, 455/65, 455/67.1, 455/67.3, 455/73, 455/296, 455/33.1, 455/60, 455/58, 455/557, 375/221, 375/222, 375/284, 375/285, 375/296, 379/59
• US Class Current: 455/63.1
• CPC Class Codes: H04B 1/62 for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters

Abstract

a modem that measures the received signal, characterizes the aptitude and phase distortion of the received signal across the bandwidth of the communication channel and pre-distorts the signal that is transmitted such that the introduced predistortion and the distortion in the channel cancel each other.

Claims

1. A system to reduce a distortion in a communication between a first and a second modem coupled together by a transmission channel that is in part wireless, wherein said communication includes transmissions and receptions by each modem, the system comprising:

an adaptive compensation module associated with said first modem to repeatedly measure the distortion in a wireless communication protocol control signal received at said first modem, said wireless communication protocol control signal being inherent in said wireless part of said transmission channel, and having a known waveform, said adaptive compensation module to unilaterally and repeatedly generate a pre-distortion signal based upon said measured distortion but transformed such that said pre-distortion signal tends to cancel said distortion; and

a pre-distortion filter associated with said first modem to introduce into said transmissions from said first modem said pre-distortion signal.

2. The system of claim 1 wherein said pre-distortion filter comprises a baseband filter.

3. The system of claim 1 wherein said pre-distortion filter comprises a passband filter.

4. The system of claim 1 wherein said adaptive compensation module includes automatic gain control.

5. The system of claim 1 wherein said adaptive compensation module includes equalization.

6. The system of claim 1 wherein said adaptive compensation module includes interpolation.

7. The system of claim 1 wherein said modem comprises:

a data pump to perform modem signal processing;

a cellular transceiver communicatively coupled to said data pump to perform cellular signaling protocols and signal conditioning;

a radio transceiver communicatively coupled to said cellular transceiver to transmit and receive control commands and radio waves; and

a single system control unit to control said data pump, said cellular transceiver, and said radio transceiver so that said data pump, said cellular transceiver, and said radio transceiver operate under a single operating system.

8. The system of claim 7 wherein both said data pump and said cellular transceiver operate in one domain.

9. The system of claim 8 wherein said modem further includes an audio unit.

10. The system of claim 7 wherein said data pump and said cellular transceiver operate in a digital domain.

11. The system of claim 10 wherein said data pump, said cellular transceiver and said system control unit are in a single digital signal processing chip or in a single microprocessor chip.

12. A communication system connected to a host computer for communicating digital data over a telephone network that is in part wireless, said system comprising:

a radio transceiver for transmitting and receiving radio frequency signals;

a D/A and A/D unit communicating with said radio transceiver, said D/A and A/D unit being adapted to convert information between the digital and analog domains;

a digital cellular transceiver communicating with said D/A and A/D unit, said digital cellular transceiver being adapted to convert data signals to digital cellular signals;

a data conditioning unit communicating with said host computer;

an adaptive compensation module communicating with said digital cellular transceiver to receive digital cellular signals that have been converted to data signals and communicates with said data conditioning unit to supply an output signal thereto, said adaptive compensation module being adapted to generate a distortion signal that compensates for distortion in said data signals on a continuous basis, said adaptive compensation unit being further adapted to generate a pre-distortion signal that is a scaled and inverted form of said distortion signal;

a baseband filter communicating with said data conditioning unit to receive conditioned data originating in said host computer therefrom and communicating with said adaptive compensation module to receive said pre-distortion signal therefrom, said base band filter being adapted to combine said conditioned data and said pre-distortion signal;

a modulator communicating with said baseband filter and said digital cellular transceiver, said modulator being adapted to modulate data into the bandwidth of said telephone network.

13. A method to reduce distortion in a communication between a first and a second modem coupled together by a transmission channel that is in part wireless, wherein said communication includes a transmit signal and a receive signal at each modem, said method comprising:

monitoring a wireless communication protocol control signal inherent in said wireless part of said transmission channel, and having a known waveform at said first modem;

measuring said distortion in said wireless communication protocol control signal repeatedly;

repeatedly and unilaterally generating a pre-distortion signal that is a scaled and inverted form of said measured distortion by said first modem; and

introducing said pre-distortion signal to said transmit signal from said first modem.

14. The method of claim 13 wherein said measuring the distortion in said wireless communication protocol control signal at said first modem includes measuring the gain of said receive signal.

15. The method of claim 13 wherein said measuring the distortion in said wireless communication protocol control signal at said first modem includes measuring the echoes included in said receive signal.