Smart dynamic selection of error correction methods for DECT based data services

• US 6,182,264 B1
• Filed: 05/22/1998
• Issued: 01/30/2001
• Est. Priority Date: 05/22/1998
• Status: Expired due to Fees

• Current Assignee: VLSI Technology, Inc. (Koninklijke Philips N.V.)
• Original Assignee: VLSI Technology, Inc. (Koninklijke Philips N.V.)
• Inventors: Ott, Stefan
• Primary Examiner(s): Baker, Stephen M.
• Application Number:
  US09/083,642
• Time in Patent Office: 984 Days
• Field of Search: 714/774, 714/751
• US Class Current: 714/774
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit
• CPC Class Codes: H03M 13/15 Cyclic codes, i.e. cyclic shifts of codewords produce other codewords, e.g. codes defined by a generator polynomial, Bose-Chaudhuri-Hocquenghem [BCH] codes H03M13/17 takes precedence
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H03M 13/3707 Adaptive decoding and hybrid decoding, e.g. decoding methods or techniques providing more than one decoding algorithm for one code
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/1816 with retransmission of the same, encoded, message
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions

Abstract

A dynamic error correction system for a bi-directional digital data transmission system. The transmission system of the present invention includes a transmitter adapted to encode information into a signal. A receiver receives the signal and decodes the information encoded thereon. The signal is transmitted from the transmitter to the receiver via a communications channel. A signal quality/error rate detector is coupled to the receiver and is adapted to detect a signal quality and/or an error rate in the information transmitted from the transmitter. The receiver is adapted to implement at least a first and second error correction process, depending upon the detected signal quality/error rate. The first error correction process is more robust and more capable than the second error correction process. The receiver coordinates the implemented error correction process with the transmitter via a feedback channel. The receiver dynamically selects the first or second error correction process for implementation in response to the detected signal quality/error rate and coordinates the selection with the transmitter such that error correction employed by the receiver and transmitter is tailored to the condition of the communications channel.

Claims

1. A dynamic error correction system for a bi-directional digital data transmission system, comprising:

a transmitter adapted to encode information into a signal;

a receiver adapted to receive said signal and decode said information encoded thereon, wherein said signal is transmitted from said transmitter to said receiver via a communications channel;

an error rate detector coupled to said receiver, said error rate detector adapted to detect an error rate in said information transmitted from said transmitter;

a processor coupled to said receiver, said processor adapted to implement at least a first error correction process and a second error correction process for said receiver, wherein said second error correction process is of a higher capability than said first error correction process; and

said processor coupled to receive said error rate from said receiver via a feedback channel within said communications channel and dynamically select said first error correction process or said second error correction process in response thereto such that error correction employed by said receiver matches the condition of said communications channel, said receiver adapted to use said second error correction process to decode information on said communication channel while said transmitter uses said first error correction process to decode information on said feedback channel.

2. The system of claim 1, wherein said feedback channel is a low capacity channel such that communication between said receiver and said transmitter is asymmetric.

3. The system of claim 1, wherein said second error correction process causes an additional amount of error correction code to be encoded into said information transmitted from said transmitter in comparison to said first error correction process, such that said second error correction process is more resistant to noise in said communications channel than said first error correction process.

4. The system of claim 3, wherein said processor is configured to select said first error correction process when said error rate is in a low state and select said second error correction process when said error rate is in a higher state such that the bandwidth of said communications channel used by said error correction code corresponds to said error rate.

5. The system of claim 3, wherein said processor is configured to select said first error correction process when said error rate is in a low state and select said second error correction process when said error rate is in a higher state such that a processing load for processing said error correction code corresponds to said error rate.

6. The system of claim 3, wherein said processor is configured to select said first error correction process when said error rate is in a low state and select said second error correction process when said error rate is in a higher state such that power consumed while processing said error correction code corresponds to said error rate.

7. A dynamic error correction system for a bi-directional digital data transmission system, comprising:

a transmitter adapted to encode information into a signal;

a receiver adapted to receive said signal and decode said information encoded thereon, wherein said signal is transmitted from said transmitter to said receiver via a communications channel;

an error rate detector coupled to said receiver, said error rate detector adapted to detect an error rate in said information transmitted from said transmitter;

a first decoder coupled to said receiver, said first decoder adapted to implement a first error correction process for said receiver;

a second decoder coupled to said receiver, said second decoder adapted to implement a second error correction process for said receiver, wherein said second error correction process is of a higher capability than said first error correction process; and

a selector coupled to receive said error rate from said receiver via a feedback channel within said communications channel and dynamically select said first decoder or said second decoder for use with said receiver in response thereto such that error correction employed by said receiver matches the condition of said communications channel, said receiver adapted to use said second error correction process to decode information on said communication channel while said transmitter uses said first error correction process to decode information on said feedback channel.

8. The system of claim 7, wherein said feedback channel is a low capacity channel such that communication between said receiver and said transmitter is asymmetric.

9. The system of claim 7, wherein said transmitter and said receiver are a DECT (digital enhanced cordless telephony) based transmitter and receiver.

10. The system of claim 7, wherein said second error correction process causes an additional amount of error correction code to be encoded into said information transmitted from said transmitter in comparison to said first error correction process, such that said second error correction process is more resistant to noise in said communications channel than said first error correction process.

11. The system of claim 10, wherein said selector is configured to select said first decoder when said error rate is in a low state and select said second decoder when said error rate is in a higher state such that the bandwidth of said communications channel used by said error correction code corresponds to said error rate.

12. The system of claim 10, wherein said selector is configured to select said first decoder when said error rate is in a low state and select said second decoder when said error rate is in a higher state such that a processing load for processing said error correction code corresponds to said error rate.

13. The system of claim 10, wherein said selector is configured to select said first decoder when said error rate is in a low state and select said second decoder when said error rate is in a higher state such that power consumed while processing said error correction code corresponds to said error rate.

14. A method for a dynamic error correction system for a bi-directional digital data transmission system, the method comprising the steps of:

a) transmitting a signal having information encoded thereon using a transmitter;

b) decoding said signal to obtain said information using a receiver, wherein said receiver receives said signal via a communications channel;

c) detecting an error rate in said information using an error detector coupled to said receiver;

d) implementing a first error correction process for said receiver when said error rate is in a low state;

e) implementing a second error correction process for said receiver when said error rate is in a higher state, wherein said second error correction process is of a higher capability than said first error correction process, the state of said error correction process detected via a feedback channel within said communications channel; and

f) dynamically selecting said first error correction process or said second error correction process in response to said error rate such that error correction employed by said receiver matches the condition of said communications channel, wherein said receiver is adapted to use said second error correction process to decode information on said communication channel while said transmitter uses said first error correction process to decode information on said feedback channel.

15. The method of claim 14, further including the steps of:

g) detecting a signal quality of said information using a signal quality detector coupled to said receiver;

h) implementing a first error correction process for said receiver when said signal quality is in a low state;

i) implementing a second error correction process for said receiver when said signal quality is in a higher state, wherein said second error correction process is of a higher capability than said first error correction process; and

j) dynamically selecting said first error correction process or said second error correction process in response to said signal quality such that error correction employed by said receiver matches the condition of said communications channel.

16. The method of claim 14, wherein said second error correction process causes an additional amount of error correction code to be encoded into said information transmitted from said transmitter in comparison to said first error correction process, such that said second error correction process is more resistant to noise in said communications channel than said first error correction process.

17. The method of claim 16, further including the step of:

implementing said first error correction process or said second error correction process in response to said error rate such that the bandwidth of said communications channel used by said error correction code corresponds to said error rate.

18. The method of claim 16, further including the step of:

implementing said first error correction process or said second error correction process in response to said error rate such that a processing load for processing said error correction code corresponds to said error rate.

19. The method of claim 16, further including the step of:

implementing said first error correction process or said second error correction process in response to said err or rate such that power consumed while processing said error correction code corresponds to said error rate.