Dummy burst detecting method and apparatus

• US 8,374,288 B1
• Filed: 07/16/2007
• Issued: 02/12/2013
• Est. Priority Date: 09/18/2006
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Kuo, Chun-Ming, Chang, I-Ping, Chen, YingYing, Fu, Hung-Shiun, Sun, Wei-nan
• Primary Examiner(s): FILE, ERIN M
• Application Number:
  US11/778,198
• Time in Patent Office: 2,038 Days
• Field of Search: 375/340
• US Class Current: 375/340
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits

Abstract

A dummy burst detection method. The method begins with generating a dummy burst nominal power η_DB² of a received burst and a normal burst nominal power η_NB² of the received burst, wherein the dummy burst nominal power η_DB² is generated based on the hypotheses that the received burst is a dummy burst, and the normal burst nominal power η_NB² is formed based on the hypotheses that the received burst is a normal burst. A likelihood of the received burst is determined according to the dummy burst nominal power η_DB², the normal burst nominal power η_NB², and the noise power of the received burst.

Claims

1. A method for detecting a dummy burst, comprising:

generating a dummy burst nominal power of a received burst, wherein the dummy burst nominal power is formed according to a first hypothesis that the received burst is a dummy burst;

generating a normal burst nominal power of the received burst, wherein the normal burst nominal power is formed according to a second hypotheses that the received burst is a normal burst;

determining that the received burst is a dummy burst when the likelihood exceeds a first threshold;

generating a noise power of the received data; and

determining a likelihood of the received burst according to the dummy burst nominal power, the normal burst nominal power, a noise power of the received burst.

2. The method as claimed in claim 1, wherein the step of generating the noise power σ

² comprises;

selecting a larger one of the dummy burst nominal power and the normal burst nominal power ^max[η

_DB²,η

_NB²];

generating the expectation of the square of received burst ^E[r2]; and

subtracting ^E[r2]with the selected nominal power ^max[η

_DB²,η

_NB²]to obtain the noise power <sup>σ

2</sup>.

3. The method as claimed in claim 2, wherein the likelihood is derived by

4. The method as claimed in claim 2, wherein the received burst is a GSM burst, and the likelihood is derived by

5. The method as claimed in claim 1, wherein the step of generating the dummy burst nominal power further comprises:

generating a radio frequency channel (C0) nominal power, wherein the C0 nominal power is formed according to a third hypotheses that the received burst is a dummy burst with a C0 sequence;

generating a Corresponding Training Sequence Code (CTSC) nominal power, wherein the CTSC nominal power is formed according to a fourth hypotheses that the received burst is a dummy burst with a mapped sequence CTSC; and

comparing the C0 nominal power and the CTSC nominal power and selecting a larger one between the C0 nominal power and the CTSC nominal power as the dummy burst nominal power.

6. The method as claimed in claim 1, wherein the step of generating the normal burst nominal power further comprises:

generating a GMSK nominal power, wherein the GMSK nominal power is formed according to a fifth hypotheses that the received burst is a normal burst modulated by Gaussian Minimum Shift Keying (GMSK);

generating an EPSK normal burst nominal power, wherein the EPSK normal burst nominal power is formed according to a sixth hypotheses that the

received burst is a normal burst modulated by 8-ary Phase Shift Keying (EPSK);

comparing the GMSK nominal power and the EPSK normal burst nominal power and selecting a larger one between the GMSK nominal power and the EPSK normal burst nominal power as the normal burst nominal power.

7. A system for detecting a dummy burst, comprising:

a dummy burst nominal power unit for generating a dummy burst nominal power of a received burst, wherein the dummy burst nominal power is formed according to a first hypothesis that the received burst is a dummy burst;

a normal burst nominal power unit for generating a normal burst nominal power of the received burst, wherein the normal burst nominal power is formed according to a second hypothesis that the received burst is a normal burst;

a likelihood unit generating a noise power of the received burst, wherein the likelihood of the received burst is determined according to the dummy burst nominal power, the normal burst nominal power and the noise power of the received burst; and

a decision unit determining whether the received burst is a dummy burst according to the likelihood.

8. The system as claimed in claim 7, wherein the likelihood unit selects the larger of the dummy burst nominal power and the normal burst nominal power max[η

_DB²,η

_NB²], generates the expectation of the square of received burst E[r²], and subtracts E[r²] with the selected nominal power max[η

_DB²,η

_NB²] to obtain the noise power σ

².

9. The system as claimed in claim 8, wherein the likelihood is derived by

10. The system as claimed in claim 9, wherein the likelihood is derived by

11. The system as claimed in claim 7, wherein the dummy burst nominal power unit generates a radio frequency channel (C0) nominal power and a Corresponding Training Sequence Code (CTSC) nominal power and selects the larger of C0 nominal power and the CTSC nominal power as the dummy burst nominal power, wherein the C0 nominal power is formed according to a third hypotheses that the received burst is a dummy burst with a C0 sequence, and the CTSC nominal power is formed according to a fourth hypotheses that the received burst is a dummy burst with a mapped sequence CTSC.

12. The sytem as claimed in claim 7, wherein the normal burst nominal power unit generates a GMSK nominal power and a EPSK normal burst nominal power and selects the larger of GMSK nominal power and the EPSK normal burst nominal power as the normal burst nominal power, wherein the GMSK nominal power is formed according to a fifth hypothesis that the received burst is modulated by GMSK, and the EPSK normal burst nominal power formed according to a sixth hypothesis that the received burst is modulated by EPSK.

13. The system as claimed in claim 9, further comprising a diversity unit collecting all likelihoods of the received bursts among a received data block and obtaining an averaged likelihood of the received data block according to the collected likelihoods, wherein the decision unit further determines whether the received data block is a dummy burst block according to the averaged likelihood.

14. A method for detecting a dummy burst, comprising:

generating a dummy burst nominal power of a received burst, wherein the dummy burst nominal power is formed according to a first hypothesis that the received burst is a dummy burst;

generating a normal burst nominal power of the received burst, wherein the normal burst nominal power is formed according to a second hypotheses that the received burst is a normal burst;

determining a likelihood of the received burst according to the dummy burst nominal power and the normal burst nominal power;

determining that the received burst is a dummy burst when the likelihood exceeds a first threshold;

collecting all likelihoods of the received bursts among a received data block;

obtaining an averaged likelihood of the received data block according to the collected likelihoods; and

determining that the received data block is a dummy burst block when the averaged likelihood exceeds a second threshold.

15. A system for detecting a dummy burst, comprising:

a dummy burst nominal power unit for generating a dummy burst nominal power of a received burst, wherein the dummy burst nominal power is formed according to a first hypothesis that the received burst is a dummy burst;

a normal burst nominal power unit for generating a normal burst nominal power of the received burst, wherein the normal burst nominal power is formed according to a second hypothesis that the received burst is a normal burst;

a likelihood unit determining a likelihood of the received burst according to the dummy burst nominal power and the normal burst nominal power; and

a decision unit determining whether the received burst is a dummy burst according to the likelihood;

a likelihood collecting unit for unit collecting all likelihoods of the received bursts among a received data block;

an averaged likelihood unit for obtaining an averaged likelihood of the received data block according to the collected likelihoods; and

a second decision unit for determining that the received data block is a dummy burst block when the averaged likelihood exceeds a second threshold.