Method and system for improving voice quality in cordless communications

• US 6,651,207 B1
• Filed: 08/20/1999
• Issued: 11/18/2003
• Est. Priority Date: 08/20/1999
• Status: Expired due to Term

• Current Assignee: Sonohm Licensing LLC (IP Edge LLC)
• Original Assignee: Siemens Information And Communication Mobile LLC (Siemens AG)
• Inventors: Sydon, Uwe, Sastrodjojo, Paulus, Dicker, Olaf, Kockmann, Juergen
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): Torres, Joseph D.
• Application Number:
  US09/378,189
• Time in Patent Office: 1,551 Days
• Field of Search: 714/704, 714/746, 375/132, 375/227
• US Class Current: 714/746
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04B 2001/7154 with means for preventing interference
• 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 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04M 1/72511 Searching for available channels
• CPC Class Codes: H04M 2250/02 including a Bluetooth interface
• CPC Class Codes: H04M 2250/08 home cordless telephone systems using the DECT standard
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal

Abstract

The present invention comprises a system and method for improving voice quality of cordless communications. The system comprises at least one mobile unit having circuitry for maintaining an individual communication link with a base station. The system also has logic residing in the base station for selecting a frequency to maintain the communication link, monitoring parameters relating to the quality of the frequency, and performing data correction on the frequency in response to the monitored quality of the frequency.

Claims

1. A system for improving voice quality in cordless communications, comprising:

a) at least one mobile unit operable to transmit and receive data at a plurality of frequencies over a communication link; and

b) a base station operable to transmit and receive data over the communication link, the base station comprising logic operable to;

select a frequency from the plurality of frequencies to transmit and receive data over the communication link,

monitor during a first time period at least one parameter relating to the quality of the selected frequency,

select, after the first time period, another frequency from the plurality of frequencies to transmit and receive data over the communication link;

select, during a second time period subsequent to a selection of the another frequency, the frequency that was monitored during the first time period; and

perform, during the second time period, at least one error correction on the frequency in response to the monitored frequency quality monitored during the first time period.

2. The system of claim 1, wherein the one mobile unit comprises a plurality of mobile units and the base station responsive to the plurality of mobile units.

3. The system of claim 2, wherein the base station is operable to select a plurality of unique frequencies, each of the selected frequencies to be used for one individual communication link.

4. The system of claim 1, wherein the at least one parameter represents whether an error rate measured over the individual communication link is acceptable.

5. The system of claim 1, wherein selecting the frequency is performed according to a frequency hopping scheme.

6. The system of claim 1, wherein performing error correction comprises:

(a) marking the selected frequency on the individual communication link as bad if the quality over the individual communication link is unacceptable; and

(b) muting contents of a next transmission to be sent over the individual communication link using the bad frequency.

7. The system of claim 1, wherein performing error correction comprises:

(a) marking the selected frequency as bad if a bit-error rate measured over the individual communication link is unacceptable; and

b) retransmitting contents of a last transmission that was last sent over the individual communication link.

8. The system of claim 1, wherein performing error correction comprises at least one of suppressing data to be transmitted during the second time period using the selected frequency, retransmitting data during the second time period from a previous transmission, instructing the mobile unit during the second time period to ignore the data previously transmitted over the selected frequency, and instructing the mobile unit during the second time period to utilize data from a previous transmission.

9. The system of claim 1, wherein the logic is further operable to block future selection of the first frequency.

10. The system of claim 1, wherein:

the selected frequency comprises one of a plurality of frequencies in a frequency subset; and

the logic is further operable to block future selection of all frequencies in the frequency subset.

11. A method for improving voice quality in cordless communications, comprising:

selecting a unique carrier frequency over an individual communication link, the communication link operable to carry data between at least one mobile unit and a base station;

monitoring the quality of the selected frequency during a first time period;

selecting another frequency after the first time period to transmit and receive data over the communication link;

after selecting the another frequency, selecting, during a second time period, the frequency that was monitored during the first time period; and

performing, during the second time period, error correction on the selected frequency in response to the monitored quality monitored during the first time period.

12. The method of claim 11, wherein the selecting step comprises a frequency hopping scheme.

13. The method of claim 11, wherein the monitoring step comprises determining a bit-error rate.

14. The method of claim 11, wherein the monitoring step comprises determining whether the selected frequency is encountering interference.

15. The method of claim 11, further comprising:

(a) selecting an additional plurality of unique carrier frequencies, one of the frequencies to be used to activate each individual communication link;

(b) monitoring the quality of the additional selected frequencies; and

(c) performing data correction on the additional selected frequencies if the monitored quality is unacceptable.

16. The method of claim 11, further comprising selecting the unique carrier frequency to activate a plurality of individual communication links, each of the communication links operable to transmit data to one of a plurality of mobile units and a base station.

17. The method of claim 11, wherein the performing error correction step comprises:

(a) marking the selected frequency on the individual communication link as bad if the quality over the individual communication link is unacceptable; and

(b) muting contents of a next transmission to be sent over the individual communication link using the bad frequency.

18. The method of claim 11, wherein the performing error correction step comprises:

(a) marking the selected frequency on the individual communication link as bad if the quality on the selected frequency is unacceptable; and

b) retransmitting contents of a last transmission that was last sent over the individual communication link.

19. The method of claim 11, wherein performing error correction comprises at least one of suppressing data to be transmitted during the second time period using the selected frequency, retransmitting data during the second time period from a previous transmission, instructing the mobile unit during the second time period to ignore the data previously transmitted over the selected frequency, and instructing the mobile unit during the second time period to utilize data from a previous transmission.

20. The method of claim 11, further comprising blocking future selection of the unique carrier frequency.

21. The method of claim 11, wherein the selected frequency comprises one of a plurality of frequencies in a frequency subset;

and

further comprising blocking future selection of all frequencies in the frequency subset.

22. A method for improving voice quality in cordless communications, comprising:

providing a base station and at least one mobile unit;

sending data using a selected frequency over an individual communication link between the base station and the mobile unit during a first time period, the communication link associated with the mobile unit;

evaluating, during the first time period, the selected frequency used on the associated communication link to determine the transmission quality of the selected frequency;

after the first time period, sending data using another selected frequency over the individual communication link;

after sending data using the another selected frequency, sending data during a second time period using the selected frequency that was used during the first time period;

performing, during the second time period, error correction on the selected frequency if the transmission quality was evaluated as unacceptable during the first time period; and

repeating the process for a second mobile unit.

23. The method of claim 22, wherein the selected frequency comprises a frequency obtained using a frequency hopping scheme.

24. The method of claim 22, wherein the repeating step comprises:

(a) sending data using a second frequency over the communication link associated with the second mobile unit for a third time period;

(b) evaluating the second frequency used on the associated communication link to determine the transmission quality of the second frequency; and

(c) performing error correction on the second frequency if the transmission quality is unacceptable when the second frequency is used during a fourth time period.

25. The method of claim 22, wherein the evaluating step comprises evaluating whether any signal source is interfering with the selected frequency.

26. The method of claim 22, wherein the performing step comprises:

(a) identifying the selected frequency as bad; and

(b) suppressing a next transmission of data on the bad frequency.

27. The method of claim 22, wherein performing error correction comprises at least one of suppressing data to be transmitted during the second time period using the selected frequency, retransmitting data during the second time period from a previous transmission, instructing the mobile unit during the second time period to ignore the data previously transmitted over the selected frequency, and instructing the mobile unit during the second time period to utilize data from a previous transmission.

28. The method of claim 22, further comprising blocking future use of the selected frequency.

29. The method of claim 22, wherein the selected frequency comprises one of a plurality of frequencies in a frequency subset;

and

further comprising blocking future selection of all frequencies in the frequency subset.

30. A system for improving voice quality in a cordless communications system comprising a base station, the base station operable to:

select a first frequency for a first time period;

communicate with at least one mobile unit using the first frequency;

monitor, during the first time period, at least one parameter related to the quality of the first frequency;

select at least one second frequency after using the first frequency;

communicate with the at least one mobile unit using the at least one second frequency;

select the first frequency again for a second time period; and

perform at least one error correction based on the at least one parameter monitored during the first time period, the at least one error correction performed during the second time period and while communicating with the at least one mobile unit using the first frequency.

31. A method for improving voice quality in cordless communications, comprising:

selecting a first frequency for a first time period;

communicating with at least one mobile unit using the first frequency;

monitoring, during the first time period, at least one parameter related to the quality of the first frequency;

selecting at least one second frequency;

communicating with the at least one mobile unit using the at least one second frequency;

after communicating using the at least one second frequency, selecting the first frequency again for a second time period; and

performing at least one error correction on the first frequency during the second time period while communicating with the at least one mobile unit using the first frequency, the at least one error correction selected based on the monitoring of the at least one parameter monitored during the first time period.

32. An apparatus, comprising:

software encoded on at least one computer-readable medium and operable when executed to;

select a first frequency for a first time period;

communicate with at least one mobile unit using the first frequency;

monitor, during the first time period, at least one parameter related to the quality of the first frequency;

select at least one second frequency after selecting the first frequency;

communicate with the at least one mobile unit using the at least one second frequency;

select, after the selection of the at least one second frequency, the first frequency again for a second time period; and

perform, during the second time period, at least one error correction while communicating with the at least one mobile unit using the first frequency, the at least one error correction selected based on the monitoring of the at least one parameter monitored during the first time period.