CA2394981C - Methods and apparatus for detecting cellular digital packet data (cdpd) - Google Patents
Methods and apparatus for detecting cellular digital packet data (cdpd) Download PDFInfo
- Publication number
- CA2394981C CA2394981C CA002394981A CA2394981A CA2394981C CA 2394981 C CA2394981 C CA 2394981C CA 002394981 A CA002394981 A CA 002394981A CA 2394981 A CA2394981 A CA 2394981A CA 2394981 C CA2394981 C CA 2394981C
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- prescribed
- signal
- components
- spectral
- spectral band
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- 238000000034 method Methods 0.000 title claims abstract 12
- 230000001413 cellular effect Effects 0.000 title claims abstract 8
- 230000003595 spectral effect Effects 0.000 claims abstract 39
- 230000002708 enhancing effect Effects 0.000 claims 2
- 208000015976 Corneal dystrophy-perceptive deafness syndrome Diseases 0.000 abstract 2
- 238000001514 detection method Methods 0.000 abstract 1
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- Mobile Radio Communication Systems (AREA)
Abstract
Disclosed herein are methods and apparatus for detecting the presence of a CDPD carrier in a channel of a cellular system (although the invention is broadly applicable to detecting a specific kind of carrier associated with an "overlay" system, wherein an "overlay"
system is one that shares the frequency allocation of another system on a non-cooperating basis). This specification describes a spectral estimation technique for detection of a CDPD carrier. In addition, this specification describes an MMSE (minimum mean-squared error) method that improves on the spectral estimation method.
system is one that shares the frequency allocation of another system on a non-cooperating basis). This specification describes a spectral estimation technique for detection of a CDPD carrier. In addition, this specification describes an MMSE (minimum mean-squared error) method that improves on the spectral estimation method.
Claims (12)
1. A spectral estimation method for detecting an overlay signal in a channel of a primary system, wherein the primary system has a plurality of channels in which the overlay signal might be present at any given time, and wherein the overlay signal is characterized by a clock frequency, the method comprising the steps of:
(a) determining which of the plurality of channels of said primary system are occupied by a signal by computing a ratio of spectral components within a prescribed spectral band to spectral components outside the prescribed spectral band for each of the plurality of channels;
(b) asychronously enhancing a spectral component at said clock frequency by performing a non-linear operation on each of the plurality of channels determined to be occupied by a signal in step (a); and (c) deciding whether each of the plurality of channels is occupied by an overlay signal as a function of the enhanced spectral component.
(a) determining which of the plurality of channels of said primary system are occupied by a signal by computing a ratio of spectral components within a prescribed spectral band to spectral components outside the prescribed spectral band for each of the plurality of channels;
(b) asychronously enhancing a spectral component at said clock frequency by performing a non-linear operation on each of the plurality of channels determined to be occupied by a signal in step (a); and (c) deciding whether each of the plurality of channels is occupied by an overlay signal as a function of the enhanced spectral component.
2. A method as recited in claim 1, wherein said overlay signal is a Cellular Digital Packet Data (CDPD) signal.
3. A method as recited in claim 1, wherein said primary system is a cellular telephone system.
4. A method as recited in claim 2, wherein said primary system is a cellular telephone system.
5. A method as recited in claim 1, wherein step (a) of claim 1 further comprises, with respect to each channel, the substeps:
(1) receiving signal and noise components in said channel;
(2) processing the received components to enhance noise components outside a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components outside said prescribed spectral band;
(4) comparing said ratio to a prescribed threshold value; and (5) identifying the channel as carrying a signal if said ratio exceeds said threshold.
(1) receiving signal and noise components in said channel;
(2) processing the received components to enhance noise components outside a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components outside said prescribed spectral band;
(4) comparing said ratio to a prescribed threshold value; and (5) identifying the channel as carrying a signal if said ratio exceeds said threshold.
6. A method as recited in claim 4, wherein step (a) further comprises, with respect to each channel, the substeps:
(1) receiving signal and noise components in said channel;
(2) processing the received components to enhance noise components without a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components without said prescribed spectral band;
(4) comparing said ratio to a prescribed threshold value; and (5) identifying the channel as carrying a signal if said ratio exceeds said threshold.
(1) receiving signal and noise components in said channel;
(2) processing the received components to enhance noise components without a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components without said prescribed spectral band;
(4) comparing said ratio to a prescribed threshold value; and (5) identifying the channel as carrying a signal if said ratio exceeds said threshold.
7. A system for detecting an overlay signal in a channel of a primary system, wherein the primary system has a plurality of channels in which the overlay signal might be present at any given time, and wherein the overlay signal is characterized by a prescribed clock frequency, the system comprising:
means for determining which of the plurality of channels of said primary system are occupied by a signal by computing a ratio of spectral components within a prescribed spectral band to spectral components outside the prescribed spectral band for each of the plurality of channels;
means for asynchronously enhancing a spectral component at said clock frequency by performing a non-linear operation on each of the plurality of channels determined to be occupied by a signal; and means for deciding whether each of the plurality of channels is occupied by an overlay signal as a function of the enhanced spectral component.
means for determining which of the plurality of channels of said primary system are occupied by a signal by computing a ratio of spectral components within a prescribed spectral band to spectral components outside the prescribed spectral band for each of the plurality of channels;
means for asynchronously enhancing a spectral component at said clock frequency by performing a non-linear operation on each of the plurality of channels determined to be occupied by a signal; and means for deciding whether each of the plurality of channels is occupied by an overlay signal as a function of the enhanced spectral component.
8. A system as recited in claim 7, wherein said overlay signal is a Cellular Digital Packet Data (CDPD) signal.
9. A system as recited in claim 7, wherein said primary system is a cellular telephone system.
10. A system as recited in claim 8, wherein said primary system is a cellular telephone system.
11. A system as recited in claim 7, wherein said means for determining which, if any, channel(s) of said primary system are occupied by a signal further comprises:
(1) means for receiving signal and noise components in said channels;
(2) means for processing the received components to enhance noise components without a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) means for computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components without said prescribed spectral band;
(4) means for comparing said ratio to a prescribed threshold value; and (5) means for identifying a channel as carrying a signal if said ratio exceeds said threshold.
(1) means for receiving signal and noise components in said channels;
(2) means for processing the received components to enhance noise components without a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) means for computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components without said prescribed spectral band;
(4) means for comparing said ratio to a prescribed threshold value; and (5) means for identifying a channel as carrying a signal if said ratio exceeds said threshold.
12. A system as recited in claim 10, wherein said means for determining which, if any, channel(s) of said primary system are occupied by a signal further comprises:
(1) means for receiving signal and noise components in said channels;
(2) means for processing the received components to enhance noise components without a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) means for computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components without said prescribed spectral band;
(4) means for comparing said ratio to a prescribed threshold value; and (5) means for identifying a channel as carrying a signal if said ratio exceeds said threshold.
(1) means for receiving signal and noise components in said channels;
(2) means for processing the received components to enhance noise components without a prescribed spectral band relative to noise components within said prescribed spectral band;
(3) means for computing the ratio of spectral components within said prescribed spectral band to the enhanced spectral components without said prescribed spectral band;
(4) means for comparing said ratio to a prescribed threshold value; and (5) means for identifying a channel as carrying a signal if said ratio exceeds said threshold.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/121,339 US5574750A (en) | 1993-09-14 | 1993-09-14 | Methods and apparatus for detecting a cellular digital packet data (CDPD) carrier |
| US08/121,339 | 1993-09-14 | ||
| CA002171719A CA2171719C (en) | 1993-09-14 | 1994-09-14 | Methods and apparatus for detecting cellular digital packet data (cdpd) |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002171719A Division CA2171719C (en) | 1993-09-14 | 1994-09-14 | Methods and apparatus for detecting cellular digital packet data (cdpd) |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2394981A1 CA2394981A1 (en) | 1995-03-23 |
| CA2394981C true CA2394981C (en) | 2005-07-26 |
Family
ID=25678373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002394981A Expired - Lifetime CA2394981C (en) | 1993-09-14 | 1994-09-14 | Methods and apparatus for detecting cellular digital packet data (cdpd) |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2394981C (en) |
-
1994
- 1994-09-14 CA CA002394981A patent/CA2394981C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2394981A1 (en) | 1995-03-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20140915 |