Infrared audio link in mobile phone

• US 6,031,825 A
• Filed: 07/23/1996
• Issued: 02/29/2000
• Est. Priority Date: 08/18/1992
• Status: Expired due to Fees

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Kaikuranta, Terho, Jarvensivu, Seppo, Sulavuori, Toni, Lipponen, Markku
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): Ho, Tuan Q
• Application Number:
  US08/685,053
• Time in Patent Office: 1,316 Days
• Field of Search: 370/279, 370/296, 370/312, 370/525, 370/526, 370/527, 370/506, 370/286, 370/295
• US Class Current: 370/296
• CPC Class Codes: H04B 10/1143 Bidirectional transmission
• CPC Class Codes: H04B 10/801 using optical interconnects, e.g. light coupled isolators, circuit board interconnections
• CPC Class Codes: H04L 5/1492 with time compression, e.g. operating according to the ping-pong technique
• CPC Class Codes: H04M 1/72412 using two-way short-range wireless interfaces
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A system for providing an IR-link between a mobile phone and its accessories to transmit audio, control, and data signals between them in an apparent full-duplex real time mode using a conventional half-duplex IR-transceiver with suitable FIFO registers and control means. The "direction" of the half-duplex channel is "switched" by the system which may be embodied in an IR-link module, having transmission channels for digital full-duplex audio signals, slow data messages and fast data messages, and for some control data. The module is connected to the baseband of a phone through a baseband interface (BBIF) and communicates through a media interface (MIF) and an infrared interface (IRIF) with free air space or a lightguide. A link-specific low-level protocol is used for audio and slow data message transmission but the link hardware of the module may also support other protocol implementations. The system may be implemented in hardware and/or software.

Claims

1. Apparatus capable of apparent full-duplex signal transmission, comprising:

conductor means for conducting input digital signals and output digital signals at a first rate;

buffer means, coupled to said conductor means, for storing said input digital signals received from said conductor means at said first rate;

a multiplexer, coupled to said buffer means, for reading and transmitting said input digital signals stored in said buffer means at a second rate faster than said first rate; and

a media driver, coupled to said multiplexer, for converting said input digital signals transmitted by said multiplexer into signals for external transmission;

and wherein;

said media driver receives and converts externally generated signals into received digital signals in a half-duplex mode with said input digital signals transmitted by said multiplexer;

said multiplexer transmits said received digital signals from said media driver and stores said received digital signals in said buffer means at said second rate;

said conductor means receives at said first rate said received digital signals stored in said buffer means and outputs said received digital signals as said output digital signals at said first rate; and

control means for controlling said first and second rates such that the storing of input digital signals by said buffer means and the outputting of output digital signals by said conductor means are timed to appear to be in full-duplex mode.

2. Apparatus as in claim 1 wherein said input and output digital signals comprise audio signals and further comprising:

slow data channel means for providing slowbus-messages;

a slow data channel buffer means, coupled to said slow data channel means, for storing slowbus-messages provided by said slow data channel means at a third rate slower than said second rate, and coupled to said multiplexer for transmitting slowbus-messages stored in said slow data channel buffer means to said multiplexer for multiplexing with said input digital audio signals.

3. Apparatus as in claim 2 wherein said control means comprises:

a receiving state machine; and

means for producing a signal frame that controls said receiving state machine, said signal frame including a control field and a data field, said data field comprising digital audio signal indicative bits and slowbus-message indicative bits.

4. Apparatus as in claim 3 further comprising:

a media interface, coupling said multiplexer and said media driver, for conducting said signal frame back and forth thereacross between said multiplexer and said media driver.

5. Apparatus as in claim 1 further comprising:

fast data channel means for providing fastbus-messages to said multiplexer; and

wherein said media driver comprises means for converting said fastbus-messages received from said multiplexer into data signals for external transmission.

6. Apparatus as in claim 1 wherein said buffer means comprises a FIFO register.

7. Apparatus as in claim 1 wherein said media driver comprises one of an IR transceiver and an RF transceiver.

8. Apparatus as in claim 1 further comprising:

a modulator, coupled to said conductor means, for converting said input and output digital signals to analog signals.

9. Apparatus as in claim 8 wherein said digital and analog signals comprise audio signals and further comprising:

slow data channel means for providing slowbus-messages;

slow data channel buffer means for storing said slowbus-messages at a third rate slower than said second rate, and coupled to said multiplexer for transmitting said slowbus-messages stored in said slow data channel buffer means to said multiplexer for multiplexing with said digital audio signals;

means for providing fastbus-messages to said multiplexer; and

wherein said media driver comprises means for converting said fastbus-messages received from said multiplexer into data signals for external transmission; and

interface means, connectable to a phone, for transferring said analog audio signals, slowbus-messages, and fastbus-messages between said phone and said modulator, said slow data channel buffer means, and said means for providing fastbus-messages, respectively.

10. Apparatus for use in a system capable of audio and data transmission, comprising:

audio channel means for conducting input audio signals and output audio signals;

slow data channel means for conducting slowbus-messages;

interface means for conducting said input and output audio signals and slowbus-messages thereacross;

media driver means for converting said input audio signals and slowbus-messages to audio and data signals capable of external transmission and converting received externally generated audio and data signals to output audio signals and slowbus-messages;

first buffer means for storing said input and output audio signals;

second buffer means for storing said slowbus-messages;

multiplexing means, coupling said media driver means to said first and second buffer means in half-duplex mode, for transmitting said stored input audio signals and said stored slowbus-messages from said first and second buffer means to said media driver means at a faster transmission rate than the respective rates at which they have been stored by said first and second buffer means, and for transmitting output audio signals and slowbus-messages from said media driver means to said first and second buffer means at said faster transmission rate; and

means for controlling the difference between said faster transmission rate and the storing rates by which said input and output audio signals and said slow-bus messages have been stored by said first and second buffer means to produce input and output audio signal and slowbus-message transmission across said interface means appearing to be in full-duplex mode.

11. Apparatus as in claim 10 wherein said interface means conducts analog input and output audio signals thereacross and further comprising:

means, connected between said interface means and said first buffer means, for coding said analog input audio signals and producing digital input audio signals based thereon for storing in said first buffer means, and for sampling digital output signals from said first buffer means and producing analog output audio signals based thereon for conducting by said interface means.

12. Apparatus as in claim 10 wherein said means for controlling comprises:

a state machine; and

means for producing a signal frame that controls said state machine, said signal frame including a control field and a data field, said data field comprising audio signal indicative bits and slowbus-message indicative bits.

13. Apparatus as in claim 12 further comprising:

media interface means, coupling said multiplexer means and said media driver means, for conducting said signal frame back and forth thereacross between said multiplexer means and said media driver means.

14. A method of controlling signal transmission to appear to be full-duplex signal transmission, comprising the steps of:

storing input digital signals at a first rate in a buffer;

reading and transmitting said input digital signals stored in said buffer at a second rate faster than said first rate; and

converting said input digital signals transmitted at said second rate into signals capable of external transmission;

receiving and converting externally generated signals into received digital signals in a half-duplex mode with said input digital signals converted in said converting step;

transmitting and storing said received digital signals in said buffer at said second rate;

reading out at said first rate said received digital signals stored in said buffer; and

controlling said first and second rates such that the storing of input digital signals and the reading out of received digital signals are timed to appear to be in full-duplex mode.

15. The method of claim 14 wherein said input digital signals are produced by modulating analog signals and said received digital signals are modulated into analog signals.

16. The method of claim 15 wherein said analog and digital signals comprise audio signals and further comprising the steps of:

providing slowbus-messages;

storing said slowbus-messages at a third rate, slower than said second rate, in a slowbus-message buffer; and

reading and transmitting said stored slowbus-messages from said slowbus-message buffer at said second rate and converting said slowbus-messages into data signals with said digital audio signals for external transmission therewith.

17. The method of claim 16 wherein said controlling step is implemented with a state machine, and comprises:

producing a signal frame that controls said state machine, said signal frame including a control field and a data field, said data field comprising audio signal indicative bits and slowbus-message indicative bits.

18. The method of claim 15 wherein said modulating comprises one of CVSD modulation and PCM modulation.

19. The method of claim 14 further comprising the steps of:

providing fastbus-messages; and

converting said fastbus-messages into data signals for external transmission when not converting said input digital signals.

20. The method of claim 14 wherein said buffer comprises a FIFO register.

21. The method of claim 14 wherein said signals capable of external transmission and said externally generated signals comprise IR signals.

22. A method of controlling transmission in a system capable of audio and data transmission, comprising the steps of:

receiving analog audio signals and data-containing slowbus-messages;

providing an interface for conducting analog audio signals and data-containing slowbus-messages back and forth in first and second directions thereacross;

converting said analog audio signals conducted in said first direction to digital audio signals based thereon;

storing said digital audio signals in a first buffer at a first rate;

storing said slowbus-messages conducted in said first direction in a second buffer at a second rate;

converting digital audio signals and slowbus-messages conducted in said first direction and respectively stored in said first and second buffers to audio and data signals based thereon for external transmission;

transmitting said stored digital audio signals and stored slowbus-messages from said first and second buffers by half-duplex multiplexing, at a third transmission rate faster than said first and second rates at which they have been stored in said first and second buffers, when converting to audio and data signals for external transmission;

receiving externally generated audio and data signals;

converting received externally generated audio and data signals to digital audio signals and slowbus-messages based thereon for storing respectively in

said first and second buffers;

transmitting said digital audio signals and slowbus-messages converted from received externally generated audio and data signals, by half-duplex multiplexing at said third transmission rate to said first and second buffers for storage respectively therein, when converting;

conducting said stored digital audio signals converted from received externally generated audio signals, from said first buffer in said second direction at said first rate to said interface and converting said stored digital audio signals to analog audio signals based thereon before crossing said interface;

conducting said stored slowbus-messages converted from received externally generated data signals, from said second buffer in said second direction at said second rate to said interface; and

controlling the difference between said third transmission rate and said first and second rates to produce analog audio signal and slowbus-message transmission across said interface appearing to be in full-duplex mode.

23. The method of claim 22 wherein said input analog audio signals are modulated by one of CVSD modulation and PCM modulation.

24. The method of claim 22 wherein said controlling step is implemented with a state machine, and comprises:

producing a signal frame that controls said state machine, said signal frame including a control field and a data field, said data field comprising digital audio signal indicative bits and slowbus-message indicative bits.

25. The method of claim 24 further comprising the step of:

providing a media interface for conducting said signal frame back and forth thereacross respectively for said half-duplex multiplexing.