Method and device for detecting occupation by a signal of an adjacent channel

• US 20070047682A1
• Filed: 08/31/2006
• Published: 03/01/2007
• Est. Priority Date: 09/01/2005
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Schmidt, Michael, Sachse, Eric, Haentzschel, Dirk
• Granted Patent: US 7,574,184 B2
• Time in Patent Office: Days
• US Class Current: 375/350
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

Abstract

A method for detecting occupation of an adjacent channel by a signal with the aid of a complex-valued bandpass signal having an information channel component and/or an adjacent channel component. In accordance with the invention, a) a real-valued bandpass signal is derived in that the complex-valued bandpass signal is filtered and the real component is produced from the filtered signal, b) the real-valued bandpass signal is transposed into a first baseband signal, c) the first baseband signal is filtered so that spectral components influenced by the information channel component are suppressed, and d) the first filtered signal is evaluated and a binary occupation signal is generated to indicate the occupation of the adjacent channel as a function of the evaluated first filtered signal. The invention further discloses a corresponding device for detecting occupation, as well as a transmitting/receiving device and an integrated circuit having such a device.

Claims

1. A method for detecting occupation of an adjacent channel by a signal with a complex-valued bandpass signal having an information channel component and/or an adjacent channel component, the method comprising the steps of:

deriving a real-valued bandpass signal in that the complex-valued bandpass signal is filtered and a real component is produced from the filtered signal;

transposing the real-valued bandpass signal into a first baseband signal;

filtering the first baseband signal so spectral components influenced by the information channel component are suppressed to provide a first filtered signal;

evaluating the first filtered signal; and

generating a binary occupation signal to indicate the occupation of the adjacent channel as a function of the evaluated first filtered signal.

2. The method according to claim 1, wherein the evaluation of the first filtered signal includes a median determination from values of a binary signal that is a function of the first filtered signal.

3. The method according to claim 1, wherein the evaluation of the first filtered signal includes an average value determination from values of a binary signal that is a function of the first filtered signal.

4. The method according to claim 1, wherein the evaluation of the first filtered signal comprises the following steps:

generating a first binary signal such that the values of the first filtered signal are individually evaluated;

generating a second binary signal such that the values of the first filtered signal are evaluated by a moving window; and

generating the binary occupation signal by a logic OR operation to combine the first binary signal with the second binary signal.

5. The method according to claim 4, wherein the values of the first filtered signal are individually evaluated in that their absolute values are compared with a first comparison value, and the first binary signal takes on a value of logic 1 if the corresponding absolute value of the first filtered signal exceeds the first comparison value and takes on a value of logic 0 otherwise.

6. The method according to claim 5, wherein the first comparison value is a threshold value.

7. The method according to claim 4, wherein each value of the second binary signal indicates a median of N values of a binary auxiliary signal, where N designates the window size, and the binary auxiliary signal is a function of the first filtered signal.

8. The method according to claim 7, wherein the absolute values of the first filtered signal are compared with a second comparison value, and the binary auxiliary signal takes on a value of logic 1 if the corresponding absolute value of the first filtered signal exceeds the second comparison value, and takes on a value of logic 0 otherwise.

9. The method according to claim 8, wherein the second comparison value is a threshold value.

10. The method according to claim 1, further comprising the steps of:

transposing the real-valued bandpass signal into a second baseband signal;

filtering the second baseband signal such that spectral components influenced by the adjacent channel component are suppressed to provide a second filtered signal;

evaluating the second filtered signal; and

generating the binary occupation signal as a function of the evaluated first filtered signal and the evaluated second filtered signal.

11. The method according to claim 10, wherein the first comparison value is a function of the second filtered signal.

12. The method according to claim 10, wherein the second comparison value is a function of the second filtered signal.

13. The method according to claim 1, further comprising the steps of:

detecting the data values contained in the complex-valued bandpass signal; and

terminating the detection step when the binary occupation signal indicates occupation of the adjacent channel.

14. A device for detecting occupation of an adjacent channel by a signal with a complex-valued bandpass signal having an information channel component and/or an adjacent channel component, the device comprising:

an analog filter unit that derives a real-valued bandpass signal in that the complex-valued bandpass signal is filtered and a real component is produced from the filtered signal;

a transformation unit connected to the analog filter unit and that transposes the real-valued bandpass signal into a first baseband signal;

a digital filter unit connected to the transformation unit and that filters the first baseband signal such that spectral components influenced by the information channel component are suppressed, and to provide a first filtered signal; and

an evaluation unit connected to the digital filter unit and that evaluates the first filtered signal and generates a binary occupation signal to indicate the occupation of the adjacent channel as a function of the evaluated first filtered signal.

15. The device according to claim 14, wherein the evaluation unit has a median determination unit that determines a median from values of a binary signal that is a function of the first filtered signal.

16. The device according to claim 14, wherein the evaluation unit has an average value determination unit that determines an average from values of a binary signal that is a function of the first filtered signal.

17. The device according to claim 14, wherein the evaluation unit comprises:

a first evaluation unit connected to the digital filter unit and generates a first binary signal in that the values of the first filtered signal are individually evaluated;

a second evaluation unit connected to the digital filter unit and generates a second binary signal in that the values of the first filtered signal are evaluated by a moving window; and

an OR gate connected to the first evaluation unit and to the second evaluation unit and that generates the binary occupation signal by using a logic OR operation to combine the first binary signal with the second binary signal.

18. The device according to claim 17, wherein the first evaluation unit comprises:

an absolute-value generation unit connected to the digital filter unit and produces absolute values of the first filtered signal values;

a first decision unit connected to the absolute-value generation unit and compares the absolute values of the first filtered signal values to a first comparison value and generates the first binary signal such that it assumes a value of logic 1 if the corresponding absolute value of the first filtered signal exceeds the first comparison value and takes on a value of logic 0 otherwise.

19. The device according to claim 17, wherein the second evaluation unit has a median determination unit that generates the second binary signal such that each value of the second binary signal indicates a median of N values of a binary auxiliary signal, where N designates the window size, and the binary auxiliary signal is a function of the first filtered signal.

20. The device according to claim 19, wherein the second evaluation unit comprises:

an absolute-value generation unit connected to the digital filter unit and generates the absolute values of the first filtered signal values;

a second decision unit connected to the absolute-value generation unit and compares the absolute values of the first filtered signal values to a second comparison value and generates the binary auxiliary signal such that it assumes a value of logic 1 if the corresponding absolute value of the first filtered signal exceeds the second comparison value and takes on a value of logic 0 otherwise;

a window accumulator connected to the second decision unit and performs moving accumulation of N values of the binary auxiliary signal at a time; and

a third decision unit connected to the window accumulator and designed to generate the second binary signal such that it assumes a value of logic 1 if the corresponding accumulated value exceeds a value of essentially N/2, and takes on a value of logic 0 otherwise.

21. The device according to claim 14, wherein

the transformation unit transposes the real-valued bandpass signal into a second baseband signal,

the digital filter unit filters the second baseband signal such that spectral components influenced by the adjacent channel component are suppressed and provides a second filtered signal,

the evaluation unit evaluates the second filtered signal and generates the binary occupation signal as a function of the evaluated first filtered signal and evaluated second filtered signal.

22. The device according to claim 21, wherein the evaluation unit provides a first comparison value as a function of the second filtered signal.

23. The device according to claim 21, wherein the evaluation unit provides a second comparison value as a function of the second filtered signal.

24. The device according to claim 14, further comprising:

a control unit connected to the evaluation unit for controlling a data detection unit, which detects the data values contained in the complex-valued bandpass signal,

wherein the control unit instructs the data detection unit to terminate the current detection process when the binary occupation signal indicates occupation of the adjacent channel.

25. Transmitting/receiving device for a data transmission system according to IEEE Standard 802.15.4 in the 2.4 GHz band, comprising an antenna, a receiving unit associated with the antenna to receive data, and a device for detecting occupation of an adjacent channel according to claim 14.

26. An Integrated circuit for a transmitting/receiving device according to claim 25, having the device according to claim 14.