System and method to determine a bit error probability of received communications within a cellular wireless network

• US 7,352,720 B2
• Filed: 05/07/2004
• Issued: 04/01/2008
• Est. Priority Date: 06/16/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Wang, Yongqian, Chang, Li Fung, Yang, Baoguo, Qiu, Xiaoxin, Zeng, Huaiyu
• Primary Examiner(s): To; Doris H.
• Assistant Examiner(s): GREY, CHRISTOPHER P
• Application Number:
  US10/840,977
• Publication Number:
  US 20040252647A1
• Time in Patent Office: 1,425 Days
• Field of Search: None
• US Class Current: 370/333
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/0075 Transmission of coding parameters to receiver H04L1/0023 takes precedence
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04L 1/206 for modulated signals
• CPC Class Codes: H04L 1/208 involving signal re-encoding
• CPC Class Codes: H04L 25/067 providing soft decisions, i.e. decisions together with an estimate of reliability H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178

Abstract

RF communications received by a wireless terminal from a servicing base station are used to determine the BEP. These RF communications may be in the form of RF bursts that are part of a data frame. The signal to noise ratio (SNR) of the RF burst is determined and a sequence of soft decisions from the RF burst are extracted. The SNR maps to an estimated BEP based upon the modulation format and coding scheme of the RF burst. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). When the decoding is unsuccessful, the BEP is estimated only upon the estimated BEP derived from the SNR. Otherwise, both the estimated BEP and RBER may be used to determine the BEP.

Claims

1. A method to determine a bit error probability (BEP) of received Radio Frequency (RF) burst(s) within a data frame received from a servicing base station by a wireless terminal in a cellular wireless communication system, the method comprising:

receiving the RF burst of the data frame from the servicing base station;

determining a signal to noise ratio (SNR) of the RF burst;

extracting a sequence of soft decisions from the RF burst;

decoding the sequence of soft decisions to produce a data block;

determining whether decoding of the sequence of soft decisions was successful;

re-encoding the data block to produce a sequence of re-encoded decisions when the sequence of soft decisions decoded favorably;

comparing the sequence of soft decisions to the sequence of re-encoded decisions to produce a re-encoded bit error (RBER);

determining the BEP based on;

when decoding is unsuccessful, an estimated BEP derived from the SNR; and

when decoding is successful, the estimated BEP and the RBER.

2. The method of claim 1, wherein the sequence of soft decisions are extracted from data bits within the RF burst.

3. The method of claim 1, wherein the sequence of soft decisions are extracted from training sequences within the RF burst.

4. The method of claim 1, wherein the sequence of soft decisions are protected by fire coding and convolutional coding.

5. The method of claim 1, wherein the SNR is derived from training sequences within the RF burst.

6. The method of claim 1, wherein SNR maps to the estimated BEP based on a modulation format of the RF burst.

7. The method of claim 6, wherein the modulation format of the RF burst is GMSK or 8PSK.

8. The method of claim 1, further comprising setting the BEP to a BEP threshold when decoding is unsuccessful and the BEP threshold is greater than the estimated BEP.

9. The method of claim 8, wherein the BEP threshold is based on a Coding Scheme of the RF burst.

10. The method of claim 1, wherein the wireless terminal operates according to the GSM standard.

11. A wireless terminal that comprises:

a Radio Frequency (RF) front end;

a baseband processor communicatively coupled to the RF front end;

an enCOder/DECoder (CODEC) processing module communicatively coupled to the baseband processor;

wherein, the RF front end, the baseband processor, and the CODEC processing module are configured to;

receive a RF burst from the a servicing base station;

determine a signal to noise ratio (SNR) of the RF burst;

extract a sequence of soft decisions from the RF burst;

decode the sequence of soft decisions to produce a data block;

determine whether decoding of the sequence of soft decisions was successful;

re-encode the data block to produce a sequence of re-encoded decisions when the sequence of soft decisions decoded favorably; and

compare the sequence of soft decisions to the sequence of re-encoded decisions to produce a re-encoded bit error (RBER);

determine the Bit Error Probability (BEP) based on;

when decoding is unsuccessful, an estimated BEP derived from the SNR; and

when decoding is successful, the estimated BEP and the RBER; and

report the BEP to a servicing base station.

12. The wireless terminal of claim 11, wherein the RF front end, the baseband processor, and the CODEC processing module extract the sequence of soft decisions from data bits within the RF burst.

13. The wireless terminal of claim 11, wherein the RF front end, the baseband processor, and the CODEC processing module extract the sequence of soft decisions extracted from a training sequence within the RF burst.

14. The wireless terminal of claim 11, wherein the sequence of soft decisions are protected by fire coding and convolutional coding.

15. The wireless terminal of claim 11, wherein the SNR is derived from a training sequence within the RF burst.

16. The wireless terminal of claim 11, wherein SNR maps to the estimated BEP based on a modulation format of the RF burst.

17. The wireless terminal of claim 11, wherein the modulation format of the RF burst is GMSK or 8 PSK.

18. The wireless terminal of claim 11, wherein the soft decisions decoding unfavorably corresponds to the sequence of soft decisions having a bit error rate (BER) exceeding a threshold value, and wherein determining the BEP when the sequence of soft decisions decoded unfavorably is based upon estimated BEP and the BER exceeding the threshold value.

19. The wireless terminal of claim 11, wherein the BEP threshold is based on a Coding Scheme of the RF burst.

20. The wireless terminal of claim 11, wherein the wireless terminal operates according to the GSM standard.

21. The wireless terminal of claim 11, wherein, the RF front end, the baseband processor, and the CODEC processing module are further operable 4 e to:

process the first RF burst to produce a baseband signal; and

extract the sequence of soft decisions from the baseband signal.

22. A wireless terminal that comprises:

a Radio Frequency (RF) front end; and

a baseband processor communicatively coupled to the RF front end;

wherein, the RF front end and the base band processor are configured to;

receive the RF burst of the data frame from the servicing base station;

determine a signal to noise ratio (SNR) of the RF burst;

extract a sequence of soft decisions from the RF burst;

decode the sequence of soft decisions to produce a data block;

re-encode the data block to produce a sequence of re-encoded decisions when the sequence of soft decisions decoded favorably; and

compare the sequence of soft decisions to the sequence of re-encoded decisions to produce a re-encoded bit error (RBER);

determine the Bit Error Probability (BEP) based on;

an estimated BEP derived from the SNR of the RF burst when the sequence of soft decisions decoded unfavorably; and

the estimated BEP and the RBER when the sequence of soft decisions decoded favorably; and

report the BEP to a servicing base station.

23. The Wireless terminal of claim 22, wherein the RF front end and the baseband processor extract the sequence of soft decisions from data bits within the RF burst.

24. The wireless terminal of claim 22, wherein the RF front end and the baseband processor extract the sequence of soft decisions extracted from a training sequence within the RF burst.

25. The wireless terminal of claim 22, wherein the sequence of soft decisions are protected by fire coding and convolutional coding.

26. The wireless terminal of claim 22, wherein the SNR is derived from a training sequence within the RF burst.

27. The wireless terminal of claim 22, wherein SNR maps to the estimated BEP and based on a modulation format of the RF burst, wherein the estimated BEP is stored in memory operablye coupled to the baseband processor and the CODEC processing module.

28. The wireless terminal of claim 22, wherein the modulation format of the RF burst is GMSK or 8PSK.

29. The wireless terminal of claim 22, wherein the soft decisions decoding unfavorably corresponds to the sequence of soft decisions having a bit error rate (BER) exceeding a threshold value, and wherein determining the BEP when the sequence of soft decisions decoded unfavorably is based upon estimated BEP and the BER exceeding the threshold value.

30. The wireless terminal of claim 22, wherein the threshold value is based on a Coding Scheme of the RF burst.

31. The wireless terminal of claim 22, wherein the wireless terminal operates according to the GSM standard.

32. The wireless terminal of claim 22, wherein, the RF front end and the baseband processor are further operable to:

process the first RF burst to produce a baseband signal; and

extract the sequence of soft decisions from the baseband signal.

33. A method to determine a bit error probability (BEP) of received Radio Frequency (RF) burst(s) within a data frame received from a servicing base station by a wireless terminal in a cellular wireless communication system, the method comprising:

receiving the RF burst of the data frame from the servicing base station;

determining a signal to noise ratio (SNR) of the RF burst;

extracting a sequence of soft decisions from the RF burst;

decoding the sequence of soft decisions to produce a data block;

re-encoding the data block to produce a sequence of re-encoded decisions when the sequence of soft decisions decoded favorably;

comparing the sequence of soft decisions to the sequence of re-encoded decisions to produce a re-encoded bit error (RBER);

determining the BEP based on an estimated BEP derived from the SNR of the RF burst and the RBER, wherein;

the estimated BEP is weighed more heavily when the sequence of soft decisions decoded unfavorably;

the RBER corresponds to the sequence of soft decisions having a bit error rate (BER) exceeding a threshold value when the sequence of soft decisions decoded unfavorably; and

the RBER is weighed more heavily when the sequence of soft decisions decoded favorably.

34. The method of claim 33, wherein the sequence of soft decisions are extracted from data bits within the RF burst.

35. The method of claim 33, wherein the sequence of soft decisions are extracted from a training sequence within the RF burst.

36. The method of claim 33, wherein the sequence of soft decisions are protected by fire coding and convolutional coding.

37. The method of claim 33, wherein the SNR is derived from a training sequence within the RF burst.

38. The method of claim 33, wherein SNR maps to the estimated BEP based on a modulation format of the RF burst.

39. The method of claim 38, wherein the modulation format of the NY burst is GMSK or 8 PSK.

40. The method of claim 33, wherein the threshold value is based on a Coding Scheme of the RF burst.

41. The method of claim 33, wherein the wireless terminal operates according to the GSM standard.